See, I have set thee in God’s stead to Pharaoh, and Aaron thy brother shall be thy prophet (Exod. 7:1). Just as the lecturer sits and lectures, and the interpreter explains his words, so you shall relate everything that I have commanded, and Aaron thy brother shall speak unto Pharaoh (ibid., v. 2). Through the two of you shall all these things be done, as it is said: And Moses and Aaron did all these wonders before Pharaoh (ibid. 11:10). They both spoke to Pharaoh, even though he was told: Thou shall speak (ibid. 7:2). Moses said to Him: Master of the Universe, I will not be able to convince him with words, as it is said: A servant will not be corrected by words (Prov. 29:19).
And I will harden Pharaoh’s heart, etc. (Exod. 7:3). The Holy One, blessed be He, declared: Moses, you shall speak, and I will bring the plague. Moreover, He stated, in this world I will obtain retribution from the Egyptians through the ten plagues, but in the future I will obtain retribution for you from Gog and Magog, as it is said: And I will plead against him with pestilence and with blood; I will cause to rain upon him, and upon his bands and upon the many peoples that are with him, an overflowing shower (Ezek. 38:22).