Exodus 10:2-4

Amplified Bible

² and that you may recount and explain in the hearing of your son, and your grandson, what I have done [repeatedly] to make a mockery of the Egyptians—My signs [of divine power] which I have done among them—so that you may know [without any doubt] and recognize [clearly] that I am the Lord.”

³ So Moses and Aaron went to Pharaoh and said to him, “Thus says the Lord, the God of the Hebrews: ‘How long will you refuse to humble yourself before Me? Let My people go, so that they may serve Me. ⁴ For if you refuse to let My people go, then hear this: tomorrow I will bring [migratory] locusts into your country.