Commentary for Proverbs 13:12

And so the Sages said "Man does not die with half his inclination still in his hand" and therefore they 'age' the understanding of Man so that his understanding is never calm and constantly lusting. And as the text says the "craving of a lazy man kills him", and the statement "hope deferred sickens the heart..."

Hope deferred He relies on his friend and does nothing.

makes the heart sick Heb. מחלה, brings sickness to the heart. This מחלה is not a noun like (Ex. 23:25): “And I will remove sickness (מחלה) from your midst,” but like (Lev. 11:6): “bringing up (מעלת) the cud.”