Exodus 12:37-42

37The Israelites journeyed from Rameses to Succoth1 with about 600,000 men on foot, besides women and children. 38And a mixed multitude also went up with them, along with great droves of livestock, both flocks and herds.

39Since their dough had no leaven, the people baked what they had brought out of Egypt into unleavened loaves. For when they had been driven out of Egypt, they could not delay and had not prepared any provisions for themselves.

40Now the duration of the Israelites’ stay in Egypt2 was 430 years. 41At the end of the 430 years, to the very day, all the LORD’s divisions went out of the land of Egypt. 42Because the LORD kept a vigil that night to bring them out of the land of Egypt, this same night is to be a vigil to the LORD, to be observed by all the Israelites for the generations to come.