Therefore keep the words of this covenant and do them, that you may prosper in all that you do.
Now that Moses had largely repeated the commands which the people were to observe as their part of the covenant, and the promises and threatenings which God would make good (according as they behaved themselves) as part of the covenant, the whole is here summed up in a federal transaction.
Commenting on Deuteronomy 29:1-9
Keep therefore the words of this covenant, and do them,.... To do which they were laid under great obligations, through the goodness of God to them, in giving them victory over the two kings, and delivering their countries into their hands, as well as by all the favours bestowed on them in the wilderness, where they were sufficiently supplied with food, drink, and raiment; all...
Deu 29:9 These benefits from the Lord demanded obedience and fidelity. “Keep the words of this covenant,” etc. (cf. Deu 8:18). השׂכּיל, to act wisely (as in Deu 32:29), bearing in mind, however, that Jehovah Himself is the wisdom of Israel (Deu 4:6), and the search for this wisdom brings prosperity and salvation (cf. Jos 1:7-8).