Exodus 12:40-42

Now the time that the children of Israel dwelt in Egypt was four hundred and thirty years. And it came to pass at the end of four hundred and thirty years, even the selfsame day it came to pass, that all the hosts of Jehovah went out from the land of Egypt. It is a night to be much observed unto Jehovah for bringing them out from the land of Egypt: this is that night of Jehovah, to be much observed of all the children of Israel throughout their generations.