Musar su Deuteronomio 31:2

When G–d said to Moses: רב לך אל תוסף דבר, this amounted to the rejection of Moses' prayers not to be saddled with such problems as the סוד העיבור. Originally Moses had been the "father of all the prophets." When G–d said: רב לך, He indicated that in subsequent generations [if Moses were to go on living Ed.] he would need to consult other Torah scholars, i.e. רב לך since his own intellectual powers would decline. We have a hint of this in Isaiah 40,14. Even in Moses' own lifetime the Torah has him say לא אוכל עוד לצאת ולבא (Deut. 31,2) "I no longer can master the intricacies of Torah studies" (Sotah 13b). He did not refer to his physical prowess, since the Torah itself (Deut. 34,7) testifies that לא נס לחה that Moses had not lost any of his physical vitality. On occasion he had to draw on the memory or resourcefulness of Joshua. This is another meaning of the words רב לך, i.e. "you already have another teacher." There is also a hint of the entire development of Moses' prophecy, his rise and decline, in Deut. 18,18: נביא אקים להם מקרב אחיהם כמוך, "I will raise up a prophet for them from their own people like yourself." The respective first letters in the opening three words of this verse form the acronym אלם, silent, dumb, suggesting that at the beginning of his prophetic career Moses was silent and the entire input was G–d's. Later on, prophetic utterances would flow from him directly, i.e. מקרב. Still later he would rise to an even higher level when G–d would command him and speak with him publicly.