1)
Why does the Torah use the double expression "Im Shamo'a Tishma"?
1.
Rashi: 'If you will heed Hashem's Voice when you have little, He will enable you to continue to do so when you have a lot'.
2.
Rosh (on 28:1) #1: 'If you listen to [Divrei Torah] in this world, you will merit to hear them in the world to come'.
3.
Rosh (28:1) #2: 'If you will heed your Rebbi, in the end you will teach others'.
