What is true Christianity based on? That Jesus, the Son of God, died to save us from our sins. When those who realise that they need this salvation repent from their sins and trust in Jesus as their Saviour, they receive forgiveness of their sins and begin to increasingly experience salvation from the power of sin in their lives. This is how it ought to be for every single person who wants to be a Christian, whether they come from inside or outside of a Christian background. In fact, God doesn't take any one into His kingdom any other way (Jn.3:3;10:1).
But what is happening all around the world is that many people think they are coming to Jesus just because they see Him as a Healer, Teacher, King, etc., without going through the path of repentance from sin. In fact, many preachers are proclaiming Jesus nowadays without any reference to sin at all! They seem to think that as long as people come to Jesus that will be all right! But sadly, most of such people who come to Jesus in any other way than as to their Saviour from their sins, remain more of less the same in their lives as before. Some people subsequently get to see Jesus as their Saviour and move forward. But others remain convinced that they are Christians because they have given recognition to Jesus in some way. Some of these people go to Bible colleges and begin afterwards to 'pastor' churches! But we can imagine the condition of people in such churches!
If only people would get back to the Bible! See what it says about Jesus, sin, God's love for us, His hatred for sin, and the plan He has made for saving us. See what is insufficient for our salvation, and what is necessary. We wish we could say, listen to your pastor! That has become very unreliable these days. Go back to the Bible where you can see the truth for yourself.
Many people say with some amount of disdain that they don't waste their time with doctrine but that as long as they believe in Jesus, everything would be ok. But nowadays the situation is that you might be believing in a wrong idea about Jesus or what He said. Such is the large scale permeation of wrong doctrines into Christianity.
How do we know which the truth is when there is so much or misrepresentation all around? Look for the doctrine that leads to godliness (1Tim.6:3). Here 'godliness' refers to a real, godly character seen in practical life – walking as Jesus walked – and not merely religious practices such as a lot of Bible reading, prayer, church attendance, etc. If a doctrine does not lead to overcoming our sinful desires and living in a godly way, that is not very profitable, even if it is useful to some degree. That is why Paul told us to turn away from teachers who bring genealogies, philosophies, etc., that are not really useful for godliness (1Ti.1:4;Co.2:23).
We can see that the time has become short and we cannot waste our lives with frivolities. Right doctrine is needed to lead us to right living.