6 God spoke in this way: that his offspring would live as aliens in a strange land, and that they would be enslaved and mistreated for four hundred years.
Acts 7:6 Cross References - WEB
Genesis 15:13
13 He said to Abram, “Know for sure that your offspring will live as foreigners in a land that is not theirs, and will serve them. They will afflict them four hundred years.
Genesis 15:16
16 In the fourth generation they will come here again, for the iniquity of the Amorite is not yet full.”
Exodus 12:40-41
Galatians 3:17
17 Now I say this: A covenant confirmed beforehand by God in Christ, the law, which came four hundred thirty years after, does not annul, so as to make the promise of no effect.