ספר בראשית

Another explanation of the simile ‎חמור גרם‎; the principal ‎reward that accrues to a person is due to the fact that since he ‎had trained himself to give in to the physical demands made upon ‎by his body [seeing that his evil urge was born with him, ‎whereas the good urge only became part of him when he was ‎thirteen years old, Ed.] from his earliest youth. He ‎therefore had to overcome tremendous resistance by the evil urge ‎once he started to resist these urges, and instead concentrated on ‎serving G’d. This is hinted at in the very letters of the name ‎יששכר‎, which may be read as ‎יש שכר‎, “there is a reward (in store).” ‎The word ‎חמור‎ is clearly reminding us of ‎חומר‎ i.e. ‎חומריות‎, ‎‎“preoccupation with purely physical concerns.” If man had not ‎been exposed to the demands made upon him by physical greed ‎and lust, how could he expect a reward for having overcome and ‎abandoned those desires?‎