Jesus speaks of attitudes in the first part of today's gospel. It is not that rich people can not get into heaven simply because they are rich, it is that very often the attitude of the rich is one of superiority over the poor.
That is the most important thing of all, the disposition of the heart. Proud, arrogant people will have no place in the kingdom. Pride and arrogance sets us at odds with God.
In heaven, God is supreme; heaven is where everyone is concerned for others, no one is superior or inferior.
Peter asks in today's gospel, what will be the reward of those who leave all and follow Jesus.
The Lord promises eternal life to those who follow him. At the time Peter heard this the Lord had not risen so he would not have grasped the full meaning of what Jesus was saying. But with the resurrection, freedom from death, is the great promise of the Christian faith.