In a land that is not theirs, i.e. in Canaan and Egypt; for though Canaan was theirs by promise, to be fulfilled in after-times, yet it was not theirs by actual donation and possession; but they were strangers in it, Genesis 17:8 Psalms 105:11,12. Four hundred years, exactly four hundred and five years; but a small sum is commonly neglected in a great number, both in sacred and profane writers. There were four hundred and thirty years between the first promise, or between the renewing and confirming of the promise by the gift of Isaac, and Israel's going out of Egypt, or God's giving of the law, Exodus 12:40 Galatians 3:17; but part of this time Abraham with his son Isaac lived in much honour and comfort; but after Isaac grew up, the affliction here mentioned began with Isaac in Canaan, and continued to him and his posterity in Egypt till this time was expired.
Related Commentaries of Genesis 15:13
Genesis 15:13
13 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;