Acts 7:17
"But as the time when [the fulfillment of] the promise [God had made] to Abraham approached, the number of people [i.e., Hebrews] in Egypt grew
Acts 7:6
And God had spoken about this [beforehand] by saying that Abraham's descendants would live in a foreign country and that they would [eventually] be ill-treated as slaves for four hundred years.
Acts 13:17
The God of Israel chose our forefathers [to be His people] and made them a great people when they lived in Egypt, and with His mighty power He led them out of it.
2 Peter 3:8-9
But do not forget this one thing, my dearly loved ones, that as the Lord [counts time], one day is like a thousand years, and a thousand years are like one day.