Matthew Henry Commentary Mark 10:17-22

"And as he was going forth into the way, there ran one to him, and kneeled to him, and asked him, Good Teacher, what shall I do that I may inherit eternal life? And Jesus said unto him, Why callest thou me good? none is good save one, [even] God. Thou knowest the commandments, Do not kill, Do not commit adultery, Do not steal, Do not bear false witness, Do not defraud, Honor thy father and mother. And he said unto him, Teacher, all these things have I observed from my youth. And Jesus looking upon him loved him, and said unto him, One thing thou lackest: go, sell whatsoever thou hast, and give to the poor, and thou shalt have treasure in heaven: and come, follow me. But his countenance fell at the saying, and he went away sorrowful: for he was one that had great possessions." — Mark 10:17-22 (ASV)

This young ruler showed great earnestness. He asked what he should do now, so that he might be happy forever. Most people ask for good to be had in this world—any good (Psalms 4:6); he asks for good to be done in this world, in order to enjoy the greatest good in the other world. Christ encouraged this inquiry by strengthening his faith and by guiding his practice.

But here is a sorrowful parting between Jesus and this young man. He asks Christ what more he should do than he has done to obtain eternal life; and Christ puts it to him, whether he indeed has that firm belief in, and that high value for, eternal life that he seems to have. Is he willing to bear a present cross in expectation of a future crown?

The young man was sorry he could not be a follower of Christ on easier terms; that he could not lay hold of eternal life and keep hold of his worldly possessions too. He went away grieved. See Matthew 6:24, Ye cannot serve God and mammon.