He who does not increase his knowledge decreases it
He says: "If he does not continue to study Torah, he will forget what he has already learned. If he does not study, Torah he deserves to die." Learning Torah is like going up an escalator which is coming down. If he stands still, he will automatically go down. A person should never think that he has learned enough. He must constantly move upward or he will go backward. Hashem created man to learn Torah. If he does not grow in Torah, there is no reason for him to live. The boy who thinks he knows everything and does not need to review it over and over again, will come back to his "gemorah" and find that he has forgotten what he has learned.