Midrasz do Wyjścia 17:10

So Joshua did as Moses had said to him … and it came to pass, when Moses held up his hand (Exod. 17:10–11). Could the hand of Moses actually wage war or cause a war to cease? This indicates that whenever the Israelites glanced upward and directed their hearts to their Father in Heaven, they were strengthened, but if not, they were defeated. Similarly, And the Lord said unto Moses: “Make thee a fiery serpent, and set it upon a pole; and it shall come to pass that everyone that is bitten, when he seeth it, shall live” (Num. 21:8). Can a serpent of bronze cause death or life? This, likewise, indicates that whenever the Israelites looked upwards and expressed their devotion to their Heavenly Father, they were healed, but if not, they were destroyed. Similarly, in the verse And the blood shall be to you for a token (Exod. 12:13), did the blood help the angel of destruction or the Israelites? The fact is that at the time the Israelites smeared blood upon their doorposts, the Holy One, blessed be He, revealed Himself and had pity upon them, as it is said: And when I see the blood, I will pass over you (ibid.) i.e., the angel of death will not be permitted to come to your homes to smite you.