Barnes' Notes on the Whole Bible

Circumcise thine heart - Compare Deuteronomy 10:16 note; Jeremiah 32:39; Ezra 11:19.

That thou mayest love the Lord - Compare Deuteronomy 6:5. Love stands first as the essential and only source of obedience.

He is thy life - Or, “that” (i. e., “to love the Lord”) “is thy life;” i. e., the condition of thy life and of its prolongation in the promised land. Compare Deuteronomy 4:40; Deuteronomy 32:47.