“Then you shall say to Aaron: Take your staff” – that is what is written: “The staff of Your strength the Lord will send from Zion” (Psalms 110:2). The Holy One blessed be He subjugates the wicked only with a staff. Why? It is because they are likened to dogs, as it is stated: “They return in the evening, they howl like a dog” (Psalms 59:15); just as it is the way of a dog to be beaten with a staff, so too, they are beaten. That is why it is stated: “The staff of Your strength” – the Holy One blessed be He said: Pharaoh is wicked. If he says to you: “Provide a wonder for you,” beat him with a staff, as it is stated: “Say to Aaron: Take your staff” (Exodus 7:19).