Charles Ellicott Commentary Deuteronomy 11:13

"And it shall come to pass, if ye shall hearken diligently unto my commandments which I command you this day, to love Jehovah your God, and to serve him with all your heart and with all your soul," — Deuteronomy 11:13 (ASV)

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. (Compare to Exodus 23:20 and following, at the close of the first code; Leviticus 26; Deuteronomy 28; and, in the New Testament, the well-known close of the Sermon on the Mount in Matthew 7, and of the parallel sermon in Luke 6).

To love the Lord your God. — “Not that you should say, ‘Look, I am a disciple so that I may become rich, so that I may be called great, so that I may receive a reward’; but whatever you 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.