i.e. The covenant of mercy or grace, which he out of his own mere grace made with them. A figure called hendiaduo.
Related Commentaries of Deuteronomy 7:12
Deuteronomy 7:12
12 Wherefore it shall come to pass, ifb ye hearken to these judgments, and keep, and do them, that the LORD thy God shall keep unto thee the covenant and the mercy which he sware unto thy fathers: