Deuteronomy 30:6

God will circumcise thine heart - This promise remains yet to be fulfilled. Their heart, as a people, has never yet been circumcised; nor have the various promises in this chapter been ever yet fulfilled. There remaineth, therefore, a rest for this people of God. Now, as the law, properly speaking, made no provision for the circumcision of the heart, which implies the remission of sins, and purification of the soul from all unrighteousness; and as circumcision itself was only a sign of spiritual good, consequently the promise here refers to the days of the Messiah, and to this all the prophets and all the apostles give witness: "for circumcision is that of the heart, in the spirit, and not in the letter," Romans 2:29; and the genuine followers of God are circumcised with the circumcision made without hands - by the circumcision of Christ," Colossians 2:11, Colossians 2:12. Hence we see these promises cannot be fulfilled to the Jews but in their embracing the Gospel of Christ. To look, therefore, for their restoration is idle and nugatory, while their obstinacy and unbelief remain.

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

30:6 And the Lord - Or, For the Lord will circumcise thine heart, will by his word and spirit change and purge thy heart from all thine idolatry and wickedness, and incline thy heart to love him. God will first convert and sanctify them, the fruit whereof shall be, that they shall return and obey God's commandments, Deuteronomy 30:8 , and then shall prosper in all things, Deuteronomy 30:9 . This promise principally respects the times of the gospel, and the grace which was to be then imparted to all Israel by Christ.