Lead someone to christ

The Bible doesn't really teach that we can't lead a person to Christ or Christianity, but it does say that we can't convert them. That is, we are perfectly capable of being the means God uses to bring a person to faith and salvation. In fact, that is exactly what we do when someone believes the gospel we tell him or her. As Paul taught in Romans 10:14, this is why preachers are so necessary: "How then will they call on Him in whom they have not believed? How will they believe in Him whom they have not heard? And how will they hear without a preacher?" Of course, in saying this, Paul did not mean to imply that our preaching is sufficient in and of itself to affect the salvation and conversion of anyone. It is just one thing on the list that God uses to save people.
That brings me to the second issue: we can't convert people, only the Holy Spirit can do that. There are many arguments for why this is so, the most basic being that as fallen people we are "totally depraved." Our total depravity leaves us with no desire and no ability to receive the gospel in a saving way (for further reading, I have a series of articles on this subject in IIIM Magazine Online in the Theology section). Because you and I have no ability to cure anyone of this total depravity, we cannot convert them. Their conversion requires divine intervention to change their hearts and restore their moral ability. Many passages demonstrate this idea (e.g. Matt. 11:25-27; Acts 16:14; 1 Cor. 2:12-14; Phil. 2:12-13).

When the Bible speaks of this change of heart and renewal of moral ability, it sometimes refers to it by terms like "regeneration" or "born again." Because man is unable to receive the gospel in his fallen state, he needs to be regenerated before he can believe the gospel. Traditionally, the statement "regeneration precedes faith" has summarized this idea. This is the idea that, logically speaking, one must be enabled by God to believe the gospel before one can actually believe it. In actual experience, regeneration generally occurs simultaneously with belief, but it is the regeneration that enables the accompanying belief. We find this idea taught in such passages as John 3:5-8
Nevertheless, the Bible does say that preaching the gospel is a useful means by which God saves sinners. As Paul put it, the gospel is "the power of God for salvation" (Rom. 1:16). We cannot be certain that God will save anyone to whom we tell the gospel, but we can be certain that he does use the means of preaching the gospel in the process of bringing people to faith. When the gospel is presented to an unbeliever, the Holy Spirit may (or may not) decide to regenerate that person to enable him/her to believe the gospel and be saved.

Reference :Ra McLaughlin