“And Jesus, looking at him, loved him, and said to him, ‘You lack one thing: go, sell all that you have and give to the poor, and you will have treasure in heaven; and come, follow me.'” (Mark 10:21)
In the previous verses of Mark 10, Jesus calls on us to trust in Him completely as little children do their parents. Now Mark shows us with an example of a man who trusted in his wealth and social status rather than in the Lord. The rich young ruler came to Jesus desiring to know what thing he needed to do to take hold of eternal life. He seemed self-confident, pretty sure of himself, of his talents and abilities, his social position and his wealth. He kept the law, but apparently was not satisfied. Something was missing. Perhaps he had grown weary of doing religious deeds or felt there must be an easier way. He wanted to know the one thing that he had do to guarantee salvation.
There is but one thing that can be done to ensure eternal life: faith in Jesus, faith that believes he died for our sins to make us all right with God. And this is, basically, what Jesus told this rich young man, the way to insure eternal life was to give up his treasures and follow Him. Jesus was offering this faith as a gift to the young man but he, sadly, was not willing to give up his goods and wealth.
Jesus did not mean that wealth and possessions are wrong in themselves. Using them to define and glorify ourselves, trusting in and depending on them rather than on the One who gives them is. Wealth can become a god we look to meet our needs. Of course anything we make more important or value more than Jesus is a god. Jesus wants us to trust him to put Him first and He will take care of our needs.