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 12:13

12:13 The blood will be a sign for you on the houses where you are, so that when I see the blood I will pass over you, and this plague will not fall on you to destroy you when I attack the land of Egypt.

Exodus 12:22

12:22 Take a branch of hyssop, dip it in the blood that is in the basin, and apply to the top of the doorframe and the two side posts some of the blood that is in the basin. Not one of you is to go out the door of his house until morning.

Exodus 29:20

29:20 and you are to kill the ram and take some of its blood and put it on the tip of the right ear of Aaron, on the tip of the right ear of his sons, on the thumb of their right hand, and on the big toe of their right foot, and then splash the blood all around on the altar.