The Lord again commanded Moses and Aaron to say unto Pharaoh, “Let my people go, that they may serve me. Else, if thou wilt not let my people go, behold, I will send swarms of flies upon thee, and upon thy servants, and upon thy people, and into thy houses; and the houses of the Egyptians shall be full of swarms of flies, and also the ground whereon they are. And I will sever in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there; to the end thou mayest know that I am the Lord in the midst of the earth. And I will put a division between my people and thy people. Tomorrow shall this sign be. And the Lord did so; and there came a grievous swarm of flies into the house of Pharaoh, and into his servants’ houses, and into all the land of Egypt; the land was corrupted by reason of the swarm of flies. And Pharaoh called for Moses and for Aaron, and said, Go ye, sacrifice to your God in the land. And Moses said, It is not meet so to do; for we shall sacrifice the abomination of the Egyptians to the Lord our God. Lo, shall we sacrifice the abomination of the Egyptians before their eyes, and will they not stone us? We will go three day’s journey into the wilderness, and sacrifice to the Lord our God, as he shall command us.” {1SP 188.1}

Herren befalede Moses og Aron atter at sige til Farao: "Lad mit folk rejse, for at de kan dyrke mig! Men hvis du ikke lader mit folk rejse, se, da sender jeg bremser over dig, dine tjenere, dit folk og dine huse, og ægypternes huse skal blive fulde af bremser, ja endog jorden, de bor på; men med Gosens land, hvor mit folk bor, vil jeg til den tid gøre en undtagelse, så der ingen bremser kommer, for at du kan kende, at jeg Herren er i landet; og jeg vil sætte skel mellem mit folk og dit folk; i morgen skal dette tegn ske!" Og Herren gjorde således: Vældige bremsesværme trængte ind i Faraos og hans tjeneres huse og i hele Ægypten, og landet hærgedes af bremserne. Da lod Farao Moses og Aron kalde og sagde: "Gå hen og bring eders Gud et offer her i landet!" Men Moses sagde: "Det går ikke an at gøre således, thi til Herren vor Gud ofrer vi, hvad der er ægypterne en vederstyggelighed; og når vi for øjnene af ægypterne ofrer, hvad der er dem en vederstyggelighed, mon de da ikke stener os? lad os drage tre dagsrejser ud i ørkenen og ofre til Herren vor Gud, således som han har pålagt os!"