John Wesley on Deuteronomy 30:10

If thou wilt hearken - This is added to warn them that they should not receive the grace of God in vain, and to teach them that the grace of God doth not discharge man's obligation to his duty, nor excuse him for the neglect of it. It is observable, that Moses calls God, the Lord thy God twelve times in these ten verses. In the threatnings of the former chapter, he is all along called the Lord, a God of power, and the judge of all. But in the promises of this chapter, the Lord thy God, a God of grace, and in covenant with thee.