John Wesley on Deuteronomy 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, Deu 30:8, and then shall prosper in all things, Deu 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.