Exodus 12:39-42

12:39 They baked cakes of bread without yeast using the dough they had brought from Egypt, for it was made without yeast – because they were thrust out of Egypt and were not able to delay, they could not prepare food for themselves either.

12:40 Now the length of time the Israelites lived in Egypt was 430 years. 12:41 At the end of the 430 years, on the very day, all the regiments of the Lord went out of the land of Egypt. 12:42 It was a night of vigil for the Lord to bring them out from the land of Egypt, and so on this night all Israel is to keep the vigil to the Lord for generations to come.