מדרש על משלי 30:5

Now Moses was keeping the flock (Exod. 3:1). Scripture states elsewhere: Every word of God is tried; He is a shield unto them that take refuge in Him (Prov. 30:5). The Holy One, blessed be He, does not confer greatness upon a man until He tests him in lesser things. Only then does He elevate him to greatness. Two great men in the world were tested and found to be faithful before He raised them to positions of greatness. He tested David by means of a sheep. What did David do? He led the sheep into the desert to keep them from feeding from the field of others, and that is why his brother Eliab said to him: With whom hast thou left those few sheep in the wilderness? (I Sam. 17:28). The Holy One, blessed be He, said to him: Thou hast been found trustworthy with regard to sheep, and so now I shall entrust My flock to you that you may shepherd them, as it is written: Thou shalt shepherd My people Israel (I Chron. 11:2). And Scripture likewise says: From following the ewes that give suck He brought him to be shepherd over Jacob, His people, and Israel, His inheritance (Ps. 78:71).

Another interpretation (of Gen. 15:1): AFTER THESE THINGS. This text is related (to Prov. 2:7): HE RESERVES UNDERSTANDING FOR THE UPRIGHT.⁶⁷Tanh.,Gen. 3:11. [What is the meaning of HE RESERVES UNDERSTANDING FOR THE UPRIGHT?] Before the world was created, the Holy One reserved the Law for Abraham, as stated (in Gen. 26:5): BECAUSE ABRAHAM HEEDED MY VOICE < AND KEPT MY CHARGE: MY COMMANDMENTS, MY STATUTES, AND MY TORAHS >. < This > teaches that Abraham kept all the commandments and all the Torahs. R. Samuel bar Nahmani said: R. Jonathan said: Our father Abraham also maintained the 'eruvim of cooked foods.⁶⁸Thus the use of torah in the plural indicates that Abraham knew even the oral Torah. See above, 3:1; below, 11:12. For a full description of the ‘eruvim of cooked foods, see Maimonides, Yad, Yom Tov 6:1-3. Thus it is stated (ibid.): BECAUSE ABRAHAM HEEDED MY VOICE. For that reason, Solomon stated (in Prov. 2:7): HE RESERVES UNDERSTANDING FOR THE UPRIGHT, [A SHIELD FOR THOSE WHO LIVE BLAMELESSLY]. The Holy One said to Abraham: You have been occupied with my Law. By your life, I am a shield for you, as stated (in Gen. 15:1): FEAR NOT, ABRAM! [I AM A SHIELD FOR YOU]. Just as, when one grasps the shield, even if darts and stones are thrown at him, he is not afraid; [so I am doing for you], as stated (in Gen. 15:1): I AM A SHIELD FOR YOU; YOUR REWARD SHALL BE VERY GREAT—not for you alone, but also for your children, if they are occupied with my Law just as you have been occupied. Thus it is stated (in Prov. 30:5): [EVERY] UTTERANCE OF GOD IS PURE, A SHIELD FOR {ALL} WHO TAKE REFUGE IN HIM. It is therefore stated (in Prov. 2:7): HE RESERVES UNDERSTANDING FOR THE UPRIGHT, [A SHIELD FOR THOSE WHO LIVE BLAMELESSLY].