Charles Ellicott Commentary Deuteronomy 10:16

"Circumcise therefore the foreskin of your heart, and be no more stiffnecked." — Deuteronomy 10:16 (ASV)

Circumcise ... your heart. —“For circumcision is that of the heart, in the spirit, and not in the letter” (Romans 2:29). The verse literally runs thus: Circumcise the foreskin of your heart, and you will harden your neck no more. It is the same line of thought as St. Paul’s (Galatians 5:16) “Walk in the Spirit, and (then) you will not fulfill the lust of the flesh.”

A great God, a mighty, and a terrible ... he does execute the judgment of the fatherless and widow. —“Behold (says Rashi) His might! And close beside His might you may find His humility.” It is not otherwise in later passages of Scripture: “He heals the broken in heart, and binds up their wounds. He tells the number of the stars, and calls them all by their names.”