Exodus 8:26-28 Amplified Bible, Classic Edition (AMPC)
26 And Moses said, It is not suitable or right to do that; for the animals the Egyptians hold sacred and will not permit to be slain are those which we are accustomed to sacrifice to the Lord our God; if we did this before the eyes of the Egyptians, would they not stone us?
27 We will go a three days’ journey into the wilderness and sacrifice to the Lord our God, as He will command us.
28 So Pharaoh said, I will let you go, that you may sacrifice to the Lord your God in the wilderness; only you shall not go very far away. Entreat [your God] for me.