Another matter, “Moses was herding” – that is what is written: “Every word of God is pure” (Proverbs 30:5); the Holy One blessed be He does not bestow greatness upon a person until He tests them with a minor matter, and only then does He elevate him to prominence. There were two preeminently great ones whom the Holy One blessed be He tested with a minor matter, and they were found trustworthy and He elevated them to prominence.
He tested David with the flocks, and he led them only to the wilderness to distance them from robbery, as Eliav4David’s older brother. said to David: “With whom did you leave those few sheep in the wilderness?” (I Samuel 17:28). This teaches that David observed [the halakha cited in] the mishna (Bava Kamma 79a–79b): One may not raise a small domesticated animal in the Land of Israel.5For that reason David shepherded his flock in the wilderness.
The Holy One blessed be He said to him: ‘You have been found trustworthy with the flocks, come and herd My flock,’ as it is stated: “From the suckling ewes He brought him” (Psalms 78:71). Likewise, regarding Moses it says: “He led the flock deep into the wilderness,” to remove them from theft [by grazing in fields belonging to others], and the Holy One blessed be He took him to herd Israel, as it is stated: “You led Your people like a flock in the hand of Moses and Aaron” (Psalms 77:21).