Also See Why NOT To Ask Jesus Into Your Heart
There is no more fundamental, vital question that anyone can ask than ‘what must I do to be saved?’ - Unfortunately, there are no end of well meaning Christians who, in answer to that life and death question, will inform you that You have to ask Jesus into your heart. The burning question is whether this phrase accurately communicates the truth of Scripture.
The Myth We Are Saved By Faith Alone
Perhaps one of the all time greatest delusions in the Christian world, is the innumerable number of people who are under the impression that, in order to be forgiven their sins and inherit eternal life, all they have to do is believe Jesus died for their sins on the cross. The vast majority of Christians would tell you to "accept Jesus as your personal savior", "ask Jesus into your heart" etc. However, while the terminology may vary, the answers would almost all boil down to all you have to do is believe... all you have to do is have faith. What one never, or very rarely, hears is that anything other than faith is required to be saved. In fact the suggestion that anything other than faith is required for salvation, is not only militantly opposed by most of Christendom, but denounced as an unbiblical, works based, false teaching. But is this true? While it is certainly a fact that the Bible teaches that faith is an essential ingredient, without which it is impossible to please God, it never ever teaches that faith is the only requirement for salvation.
What Is Holiness?
There is little or no emphasis on sin in the modern church. It lies breathing its last, buried below mega star preachers, flamboyant preaching, worship teams that could find work in many Broadway productions, large "crusades", exciting "revivals", one manmade creative program after the other, and glitz and glamour that Hollywood could be proud of. Yet the Bible says "Without Holiness, No Man Shall See God!" (Hebrews 12:14)
Is The Sinner's Prayer Effective?
Largely due to evangelists of yesteryear (Charles Finney, Dwight Moody, Billy Sunday etc.) the 'sinner's prayer' started out as the "Mourner's Seat" or "Anxious Seat" gradually evolving into the usually short and simple prayer most of us are now familiar with. (Interestingly, Pilgrim's Progress by John Bunyan published in 1678 was written as a symbolic vision of a good man's pilgrimage through life and included what could be construed as a very early version of the Sinners' Prayer.)
In and around the 1950s preachers like Billy Graham and Bill Bright made the Sinners' Prayer a popular tool for the conversion of non-Christians - people were led to believe they would be forgiven of their sins and saved if they prayed the prayer. Having people recite the same repeat-after-me prayer made sense from the point of view of the evangelists because it made it possible for hundreds of people to be 'saved' simultaneously during huge crusades. Since then the "Sinner's Prayer" (or 'salvation prayer') has become an integral part of modern evangelism.
Although there is no special formula, the prayer usually includes admitting to sin, expressing belief in and acceptance of Christ's redeeming sacrifice, and a petition for Jesus to come into the person's life. Although a few are much longer, Billy Graham's version was
Dear Lord Jesus, I know that I am a sinner, and I ask for Your forgiveness. I believe You died for my sins and rose from the dead. I turn from my sins and invite You to come into my heart and life. I want to trust and follow You as my Lord and Savior.
One or another form of the prayer is now used by a countless number of Christians as a way to 'close the deal' when leading a non-believer to Christ.
Altar Calls: The 'sinner's prayer' is also commonly used as part of the "altar call" at the end of a worship service in very many Protestant and Evangelical churches. The minister or other worship leader will invite people to ask Jesus Christ into their lives by repeating the prayer after him. (They either walk down to the altar or stay where they are)
Televangelists often introduce the prayer during their programs. Although I have no idea whether this is being done any more, one fairly common practice was asking people to touch their TV screen while praying the prayer.
Printed Tracts: The prayer is also frequently included in printed Gospel tracts that urge people to pray it from the bottom of their hearts.
Deathbed 'Confessions: Some who have lived a sinful life but recite the prayer on their death beds are considered to be saved in the nick of time.
Is It Necessary?
While it is not wrong to lead a person to pray, we need to remember that among the cases of conversion in the book of Acts there isn't a single instance of anyone reciting or being saved by any variation of this prayer.
The thief on the cross simply asked Jesus to 'remember' him when He (Jesus) came into His kingdom.
After the Ethiopian eunuch heard the Gospel from Philip he asked 'what prevented him from being baptized?" Philip's answer was "If you believe with all your heart, you may" to which the eunuch responded "I believe that Jesus Christ is the Son of God. Whereupon he was baptized by Philip. (Acts 8:35-38).
When the Philippian jailer asked Paul and Silas, "Sirs, what must I do to be saved," they simply told him to "Believe in the Lord Jesus, (Acts 16:31).
Furthermore, many, many centuries went by without a particular 'salvation' formula being used. Much to the contrary, when someone heard, believed and accepted the Gospel message they were baptized to signal their new found life. It was the first step for new believers.
The Pro's And Cons
Although the term "Sinner's Prayer" does not exist in Scripture, the concept is said to be based on Romans 10:9-10,
... if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved; for with the heart a person believes, resulting in righteousness, and with the mouth he confesses, resulting in salvation.
So theoretically, the 'sinners prayer' is a prayer that is said when someone wants to repent of their sin, ask God for forgiveness and express their belief in the life, death, and resurrection of Jesus Christ. It also gives the Christian who led the non-believer through the prayer the sense that the sought-after goal of having someone come to Christ has been realized. Additionally, it may help teach the pray-er that elaborately phrased prayers are not necessary in order to communicate with the Father.
Very many preachers and lay Christians see the Sinner's Prayer as the defining moment of one's salvation. The moment you prayed this prayer, you are saved — like a "password" to God's Kingdom. The problem is so much emphasis has been placed on the prayer that it has, however unintentionally, overshadowed and even detracted from the primary issues...
Sin - the reason we need salvation in the first place
Repentance - What we have to do to obtain forgiveness for our sins
Righteous Living - Or 'holiness' without which no one will ever see God.
Anyone who believes that uttering the Sinner's Prayer alone can save them is making a fatal mistake. We dare not forget that merely saying, "Lord, Lord" is not enough, which Jesus made very clear
"Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven, but he who does the will of My Father who is in heaven will enter. (Matthew 7:21 NASB)
"Why do you call Me, 'Lord, Lord,' and do not do what I say? (Luke 6:46 NASB)
Stop a moment to ponder 2 Corinthians 13:5 that reads, "Examine yourselves to see if your faith is really genuine. Test yourselves. If you cannot tell that Jesus Christ is among you (or in you), it means you have failed the test." Note that Paul is telling them/us to examine our present state and see if our present faith is genuine. He is not telling us to examine our past and see if we said the sinner's prayer. Doesn't it seem evident that Paul wouldn't make this statement if salvation were dependent upon a one time profession of faith that ?
The problem is we are usually inclined to interpret the English word believe as that something we think is true. However, this is not how the Bible uses it. Biblical "belief" means obedience to God's commandments. We will eventually be judged according to our deeds, because what we do is clear evidence of what we really believe.
The 'Sinners Prayer' is a dangerous simplification of the gospel message because those praying it may not understand the gravity of sin, and Christ's offer of forgiveness. As Aaron Berry contributing writer to Crosswalk.com so accurately puts it
"The Sinner's Prayer" is often reduced (perhaps not intentionally, but practically) to a formulaic, repeat-after-me approach toward conversion. In many church settings, the prayer itself is considered the entirety and assurance of salvation. In other words, as long as someone prays the right words of the "Sinner's Prayer" and "really means it," he can rest assured that he is saved... many professing Christians out there who place their assurance of salvation in a "Sinner's Prayer" when they were five years old, while they exhibit no evidence of belief in Christ. They're clinging to a prayer, not to Christ. 
Thus we have to be vigilant that we do not tell people or give them the impression in any way that they can just pray the prayer and be saved. Its their get out of hell card.
In itself no prayer can cause the gates of Heaven to swing open or ever save anyone.
Pastor Greg Koukl has voiced his concern with "some well-intentioned ambassadors for Christ" who lead people in the "sinner's prayer." In his words,
On occasion, though, I notice something alarming. When I ask if a particular person is a Christian, the response I hear is, "Well, they prayed the prayer." It's as if the words were magic; if someone just recites them, they're in.
I fear we've inoculated a whole generation of people who got a partial injection of Christianity and are now resistant to the real thing. They prayed the sinner's prayer, got their "fire insurance," and then disappeared, never to be seen again. When confronted with the Gospel anew they shrug, "Been there, done that. Now leave me alone. I have a life to live."
Here's the antidote: The goal of an ambassador should never be getting someone to pray a prayer, but rather to follow Jesus. When we emphasize deciding for Christ instead of living for Him, we often get spiritual miscarriages instead of spiritual births. Our sense of safety can't come from simply saying a prayer. 
True Conversion is Neither Based on a Single Prayer Nor on Feeling.
Far too many Christians today base their beliefs on feelings and emotions. However, although it is true that Christians are often aware within themselves that they belong to God which ties in with Paul's words
"... you have received a spirit of adoption as sons by which we cry out, ‘Abba! Father!' The Spirit Himself bears witness with our spirit that we are children of God" (Romans 8:15-16).
However, this is probably the least reliable evidence simply because human feeling can and often are influenced by all manner of things - ... from how we physically feel that day, what we might have eaten, or what our current circumstances are. Most people can probably recount many instances when they were wrong about something... when their feelings led them astray. In fact, one of the most common, and least understood, reasons behind some of our 'spiritual' feelings can very well be attributed to brain wave frequencies (the brain's spontaneous electrical activity). In fact, Buddhist meditators, Hindus, New Agers, Shamans, Witches and 'Christian' mystics all testify to the efficacy of feelings ---- as do the Mormons. See Contemplative Prayer
So is there any way a person can know whether they have truly become members of God's family?
Yes, two things!
1.) The Promises of Scripture
We don't have to rely on how we feel in order to know that we are now the Father's children. Even when confessing our sins, reading our Bibles, praying, attending church services and/or Bible studies all leave us as dry and feeling very far from God we have something unshakable to stand on - His Word. John devoted much space to the Father's promises...
But as many as received Him, to them He gave the right to become children of God, even to those who believe in His name, (John 1:12 NASB)
For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life. (John 3:16 NASB)
"For this is the will of My Father, that everyone who beholds the Son and believes in Him will have eternal life, and I Myself will raise him up on the last day." (John 6:40 NASB)
"Therefore I said to you that you will die in your sins; for unless you believe that I am He, you will die in your sins." (John 8:24 NASB)
that if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved; (Romans 10:9 NASB)
but these have been written so that you may believe that Jesus is the Christ, the Son of God; and that believing you may have life in His name. (John 20:31 NASB)
These things I have written to you who believe in the name of the Son of God, so that you may know that you have eternal life. (1 John 5:13 NASB)
2.) A Righteous Life and Endurance
However, something that is often overlooked is that the Bible is an integrated whole and from cover to cover represents the 'whole counsel of God'. This means that all passages that speak of or have any bearing on the subject in question have to be taken into consideration. With that in mind we need to pay attention to another of John's passages...
"He who believes in the Son has eternal life; but he who does not obey the Son will not see life, but the wrath of God abides on him." (John 3:36 NASB)
In fact, John went as far as to say that anyone who claims to know the Savior but does not obey the Lord's commandments is a liar.
That we have come to know Him, if we keep His commandments. The one who says, "I have come to know Him," and does not keep His commandments, is a liar, and the truth is not in him; (1 John 2:3-4 NASB)
Christ Himself and the author of Hebrews both said eternal salvation was only available to those who obeyed.
"Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven, but he who does the will of My Father who is in heaven will enter. (Matthew 7:21 NASB)
He who believes (Gk. pisteuo) in the Son has eternal life; but he who does not obey the Son will not see life, but the wrath of God abides on him. (John 3:36 NASB)
Peter listed a number of qualities including moral excellence, knowledge, self-control, perseverance, godliness, brotherly kindness, and and love adding that "he who lacks these qualities is blind or short-sighted". He then entreated his readers to "be all the more diligent to make certain about His calling and choosing you; for as long as you practice these things, you will never stumble" (2 Peter 1:5-10
The book of Hebrews warns us to
Pursue peace with all men, and the sanctification (holiness) without which no one will see the Lord. (Hebrews 12:14 NASB)
Take care, brethren, that there not be in any one of you an evil, unbelieving heart that falls away from the living God. But encourage one another day after day, as long as it is still called "Today," so that none of you will be hardened by the deceitfulness of sin. For we have become partakers of Christ, if we hold fast the beginning of our assurance firm until the end, (Hebrews 3:12-14 NASB)
James' teaching are crucial in this regard. In terms reminiscent of the Old Testament prophets he thundered,
What use is it, my brethren, if someone says he has faith but he has no works? Can that faith save him? If a brother or sister is without clothing and in need of daily food, and one of you says to them, "Go in peace, be warmed and be filled," and yet you do not give them what is necessary for their body, what use is that? Even so Even so faith, if it has no works, is dead, being by itself. But someone may well say, "You have faith and I have works; show me your faith without the works, and I will show you my faith by my works." You believe that God is one. You do well; the demons also believe, and shudder. But are you willing to recognize, you foolish fellow, that faith without works is useless? (James 2:17-20, 24-25 )
In other words, belief or faith in Christ cannot be mere intellectual assent but has to be accompanied by obedience to His commands. If prayed sincerely the Sinner's Prayer is the beginning, not the end.
Sadly, many Christians today have become so focused on the whole idea of just believing, that they have completely lost sight of the Biblical meaning of the word "faith". The Word of God nowhere supports the idea that a mental assent to Jesus having lived, died, and been resurrected is enough to save a person. Nor do the Scriptures ever state or even imply that believing that Jesus died on the cross for our sins is sufficient to give us eternal life. Much to the contrary, it states, in very unambiguous terms, that faith is not just a matter of believing, but of following through on that belief.
For more on Faith and Obedience See Why It Isn't Enough To Just Acknowledge Jesus as Savior
One of the little known facts about the New Testament is that of the twenty seven books of the New Testament sixteen books (60 percent) do not refer to Jesus as Savior even once. In fact, the numbers are astonishing. Jesus is referred to as "Lord" over six hundred times in the New Testament, but the Greek word soter, which means deliverer or savior, is used a mere 24 times in the New Testament. Yet, how many times do we read or think of Christ as 'Lord' or 'King' without paying any attention to the full implications of the term and what the great significance of this title is and what it demands of us?
But can a person be judged by his deeds when the Bible clearly tells us that we are saved by grace through faith. Is it possible to reconcile the two?
The answer is a resounding "yes". Not only can the two concepts be reconciled, but they are actually inseparable.
See The Criteria By Which We Will Be Judged on THIS Page
The next time you witness to a non-believer about Christ pass over the sinner's prayer in favor of a more complete picture of what salvation is, why we need it and how we obtain it. Tell the person about sin and its consequences, God's plan of forgiveness, and His kingdom that Jesus came to announce.
Tell them that although we are usually inclined to interpret the English word believe as that something we think is true, this is not how the Bible uses it. Biblical "belief" means obedience to God's commandments. And that we will eventually be judged according to our deeds, because what we do is clear evidence of what we really believe.
However, also assure them that God is not a celestial version of the consummate killjoy. In fact, Jesus told us to come to Him, for His burden was "light". In the New Testament, aside from loving the brethren, about the only command that is repeated over and over again in different words is to stay away from sin. For example.. "abstain from wickedness." (2 Timothy 2:19), and from every form of evil. (1 Thessalonians 5:22). Dwell on whatever is right, pure, and praiseworthy. (Philippians 4:8). In other words be holy.
 Aaron Berry. What Is the Sinner's Prayer? https://www.christianity.com/wiki/prayer/what-is-the-sinner-s-prayer.html
 Greg Koukl. Is the Sinner's Prayer Effective? https://www.cybersalt.org/guest-authors/is-the-sinners-prayer-effective