He is saying that it is impossible for a rich man to go to heaven. As impossible as a camel going through the eye of a needle.
For what reason? Seems obvious. The rich are such unrepentant sinners that they have no shot.
That's...not the point of the line at all. People need to give up the things that attach them to this world in order to have a better chance of making it into the next, and the rich simply have more tying them down here (their vast wealth makes secular life comfortable) that it becomes much harder to be willing to think of your place in the Kingdom of Heaven. Christianity isn't inherently anti-rich: look at Joseph of Arimathea, the phenomenally wealthy supporter of Jesus who bought Jesus' burial cave. He's a saint now.
