Genesis 15:13

13 Then the LORD said to him, “Know for certain that for four hundred years your descendants will be strangers in a country not their own and that they will be enslaved and mistreated there.

Read Genesis 15:13 Using Other Translations

And he said unto Abram, Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years;
Then the LORD said to Abram, "Know for certain that your offspring will be sojourners in a land that is not theirs and will be servants there, and they will be afflicted for four hundred years.
Then the LORD said to Abram, “You can be sure that your descendants will be strangers in a foreign land, where they will be oppressed as slaves for 400 years.