When God by his precepts teaches us concerning his will, he apprizes us of our misery and how wholeheartedly we disagree with his will. At the same time he prompts us to call upon his Spirit to direct us into the right path. But because our sluggishness is not sufficiently aroused by precepts, promises are added in order, by a certain sweetness, to entice us to love the precepts. The greater our desire for righteousness, the more fervent become to seek God’s grace.
– John Calvin, Institutes, II. v. 10.