To rescue people from Satan's kingdom and heal them of the damage he did to them.
To learn how to relate to The Father as His Child and to me as King and step brother.
To learn how to defeat Satan thus protecting The Kingdom, its King and its citizens.
As you do these things:
You demonstrate He is real
You demonstrate His Love
You show you belong to His Kingdom
You mature as you do these things and fight the opposition of Satan. Without any opposition there is little or no Christian maturity.
Satan could not defeat the church so joined it and guided its teaching and theology so that few teach any of the above. This is also why the Kingdom of God is so divided. If God was behind the teaching of the church the above would be taught and there would be unity of The Body!
This is also the reason that a minority of Christian will go up in the rapture and the majority will be left on earth. The church is not teaching these things.
He has taught the church not to teach the above in a way that they would put it into practice so that many Christians know of these things and learn about The Bible but do not personally know Jesus and The father or how to really represent Jesus and The Father on earth!
Remember that eternal life is a living relationship with Jesus and The father and this relationship is not taught by most churches.
So be found doing the work of Jesus when He comes and you will be Raptured. Otherwise you will be left behind with the majority of Christians in the west.