Charles Ellicott Commentary Deuteronomy 4:37

"And because he loved thy fathers, therefore he chose their seed after them, and brought thee out with his presence, with his great power, out of Egypt;" — Deuteronomy 4:37 (ASV)

Because he loved your fathers. —The reasons for God’s choice of Israel are frequently stated in this book; and they are always stated in such a way as to enforce the doctrine of God’s sovereignty, and to show the Israelites that their own merit was in no way the ground of God’s choice.