One thing Thou lackest

Mark 10:21 "Then Jesus beholding him loved him, and said unto him, One thing thou lackest: go thy way, sell whatsoever thou hast, and give to the poor, and thou shalt have treasure in heaven: and come, take up the cross, and follow me."

A young man apparently looking for the truth, he thought Jesus would flattered him because he was keeping the commandments, yet was not expecting for such a tremendous truth, he lacked sth: real love in a practical way and not only in words. Jesus mentioned almost all the commandments regarding our neighbor, and the young man said that he kept them all, but just in words and not in actions.
Jesus loved him, invited him to become a DISCIPLE, but he preferred to choose the love of these earthly things rather than self-denial and true love for God and his fellowmen.

Mark 10:22 "And he was sad at that saying, and went away grieved: for he had great possessions."