Virtually everyone who has publicly identified himself or herself as a Christian has encountered nonbelievers who base their rejection of Christianity on the apparent moral failures of individual Christians or on the reprehensible actions of Christians corporately through the centuries. While the objection is expressed in many forms, its central thrust is that the hypocrisy of Christians invalidates Christianity.
While it is true that many reprehensible deeds have been carried out through the centuries by so-called Christians, the objection is, in itself, illogical and carries with it a common misconception of the gospel of Christ. It is what is known as a ‘trivial objection’ in the study of logic where the focus is on a point less significant than the main point. However the preceding statement is not intended to detract in any way from the pain caused by Christians.
When it comes to evaluating the truth of Christianity. The central issue is whether or not the historical and factual claims of Christianity are actually true (e.g., Was Jesus of Nazareth truly the divine messiah? Did Jesus, in fact, rise from the dead?). The issue is not on Christians' success or failure in adhering to biblical principles (ethics). The wrong doing of some Christians, while never to be condoned has little bearing on the claims of Christianity. As Christian apologist John Warwick Montgomery once quipped, "If Albert Einstein’s assistant were arrested for shoplifting, would that make E=mc2 wrong?"
See Section Choose Life That you May Live
What is truly interesting is that most people seem to be prejudiced against the Bible, but well disposed towards other 'scriptures'. This is a rather illogical situation, because there is far more evidence in favor of the Bible being true, than there is for any of the other 'holy books'. This includes scientific, historical and archaeological corroboration and the many fulfilled prophecies. Also, all too many people, picking out a random phrase or two, think 'love' was Jesus' core message. Unfortunately, they are terribly wrong... the Kingdom of God, a phrase used over 50 times in the four Gospels alone, was at the heart of Jesus' ministry. But here is the interesting part, the Bible's description of this kingdom of God, also called heaven matches the world most men and women would choose to live in, one of peace and safety, where there is no crime, hunger and disease, war and above all... no death. In other words, Christianity, which appears to be outdated, out of touch, and largely irrelevant to modern society, promises exactly the utopian world that mankind can only dream of. Now, you have to decide if you want to be there.
Nonbelievers often fail to realize that according to Scripture, conversion is the beginning—not the end—of a long process of transformation. Moral and ethical perfection is not instantaneous (1 Kings 8:46; 1 John 8-10). Thus a certain level of immaturity and imperfection, including some hypocrisy (though always regrettable) can be expected among Christians. We believers spend a lifetime struggling, not to gain freedom from sin's penalty, but rather to gain freedom from sin's power over our attitudes and actions. The ultimate transformation, of course, awaits the Christian only in the eternal age to come.
See The Myth of Faith Alone and What Is Holiness?
Unfortunately, Christians reinforce the misunderstanding when we convey the message that to be a Christian means to follow a list of rules. Certainly, commitment to the Lordship of Jesus Christ demands submission to God’s authority and willingness to obey His commands, but true righteousness comes by "divine rescue": Jesus Christ has rescued us from our sin through His perfect life, sacrificial death, and glorious resurrection from the dead. Christianity is a strongly ethical faith. This does not, however, mean that Christianity is about a set of rules, in which Christians mechanically conform to a set of instructions. Rather, it is about a set of values which arises from being redeemed.
Closely related to the charge of personal hypocrisy is the more complex and grievous objection concerning all the evil done throughout history in the name of Christ (e.g., the crusades, the inquisition, the war in Northern Ireland). First, while we Christians must accept the fact that Christian history has a dark side, nevertheless we do not have to accept that all those who performed evil actions in the name of Christ were not truly Christians nor following Christ's instructions. Their actions represent the very antithesis of His expressed will. Christian philosopher Thomas V. Morris remarks,
"Certainly organizations calling themselves ‘Christian’ have often had deleterious and even disastrous effects on human society. But such movements have clearly diverged at least as far from the gospel of Christ as they have from the restraints of common morality. Sheep ought not to be judged by the actions of wolves who wear wool."
Morris also points out that religion in general, and Christianity in particular, can be a "magnet for the unscrupulous" who prey upon and exploit the sincere and trusting souls who belong to the community of faith.
Further, to blame "religious wars" exclusively on religion, on Christianity specifically, is naive. Religious wars of the past and present arise as much from economic, political, and social conflict as from religion per se.
While there is little doubt that many Christians fall depressingly short of Christian ideals countless number of Roman Catholics, Orthodox, Protestants alike have all been inspired by Christ’s life and teachings and have been deeply involved in helping the poor; the disadvantaged; the disenfranchised, and have been willing to work against their own personal interests to serve others. The missionary work, the hospitals, the orphanages, the feeding and clothing of the poor and hungry and the welfare of the sick by Christians is usually ignored by skeptics who claim that ‘the church is full of hypocrites’. See The Social And Historical Impact of Christianity