Mark 10:21-22

And I will add to that dignity. The foolish man lacks unrivaled allegiance to God since wealth is his god.

So the Kingdom of God itself is compared to an immense treasure that is worth securing at all costs, as Matthew 13:44 tells us.

The rich man has replaced genuine trust in God, and his reward, that is, treasure in heaven, with worldly riches. He thus breaks the first commandment, You shall have no other gods before Me.

This does not mean that every disciple of Christ must sell all he owns. Instead, the heart should be focused on God, and every possession should be yielded to God, with the result that possessions will be handled as a form of stewardship.

Everything is God's and everything we own is God's, and so we are stewards of it. The path to eternal life lies in turning away from reliance on self-achievements and worldly securities, and instead trusting in Jesus Christ, the Bridegroom.

Mark 10:17-22

It is not hard to determine that he feared the loss of his wealth. That is where his security was. It kept him from loving Christ. Covetousness and idolatry reared their ugly heads and stopped him cold in his tracks because he feared the loss of what he already had and he would not venture forth.