Exodus 12:37-42
37And the sons of Israel set out from Rameses to Soccoth, about six hundred thousand men on foot, besides little ones. 38But also an innumerable mix of common people ascended with them, sheep and herds and animals of diverse kinds, exceedingly many. 39And they baked the bread, which a little while ago they had taken out of Egypt as dough. And they made unleavened bread baked under ashes. For it was not able to be leavened, with the Egyptians compelling them to leave and not permitting them to cause any delay. Neither did they have occasion to prepare any meat. 40Now the habitation of the sons of Israel, while they remained in Egypt, was four hundred and thirty years. 41Having been completed, on the same day all the army of the Lord departed from the land of Egypt. 42This night is a worthy observance of the Lord, when he led them out of the land of Egypt. This all the sons of Israel must observe in their generations.