Exodus 7:19

7:19 Then the Lord said to Moses, “Tell Aaron, ‘Take your staff and stretch out your hand over Egypt’s waters – over their rivers, over their canals, over their ponds, and over all their reservoirs – so that it becomes blood.’ There will be blood everywhere in the land of Egypt, even in wooden and stone containers.”

Exodus 8:26

8:26 But Moses said, “That would not be the right thing to do, for the sacrifices we make to the Lord our God would be an abomination to the Egyptians. If we make sacrifices that are an abomination to the Egyptians right before their eyes, will they not stone us?

Exodus 17:12

17:12 When the hands of Moses became heavy, they took a stone and put it under him, and Aaron and Hur held up his hands, one on one side and one on the other, and so his hands were steady until the sun went down.