Deuteronomy 10:16
Circumcise therefore the foreskin of your heart, and be no more stiff-necked.
World English Bible (Public Domain)
In context
Before · Deuteronomy 10:14–15
14Behold, to the LORD your God belongs heaven, the heaven of heavens, and the earth, with all that is therein. 15Only the LORD had a delight in your fathers to love them, and he chose their offspring after them, even you above all peoples, as it is today.
16Circumcise therefore the foreskin of your heart, and be no more stiff-necked.