Exodus 12:37-39

37The Israelites journeyed from Rameses to Sukkoth. There were about six hundred thousand men on foot, besides women and children.

38Many other people went up with them, and also large droves of livestock, both flocks and herds.

39With the dough the Israelites had brought from Egypt, they baked loaves of unleavened bread. The dough was without yeast because they had been driven out of Egypt and did not have time to prepare food for themselves.