Deuteronomy 11:13

It shall come to pass. — At this point begins the formal sanction of this charge by a declaration of rewards and punishments. Such sanctions are a characteristic feature of the Law. (Comp. Exodus 23:20 — end, at the close of the first code; Leviticus 26, and Deuteronomy 28; and, in the New Testament, the well-known close of the Sermon on the Mount in St. Matthew 7, and of the parallel sermon in St. Luke 6)

To love the Lord your God. — “Not that thou shouldst say, ‘Behold, I am a disciple in order that I may become rich: in order that I may be called great: in order that I may receive reward; “but whatsoever ye do, do from love” (Rashi).

To serve him with all your heart. — The Jewish commentator says that this refers to prayer, and compares Daniel (Deuteronomy 6:16): “Thy God whom thou servest continually, He will deliver thee.” There was no religious service for Israel in Babylon except prayer. The thought seems worth preserving, though the words are obviously capable of a wider application.