Deuteronomy 4:40

Thou shall keep therefore his statutes, and his commandments,
&c.] All his laws, moral, ceremonial, and judicial, partly being under obligation to him for all the great and good things done by him for them before enumerated, and partly and chiefly because he is the Lord God in heaven and in earth, and has a right to command and ought to be obeyed:

which I command thee this day;
in the name of the Lord, and which he repeated, opened, and explained, and charged them afresh to observe; otherwise they were such that had been given long ago:

that it may go well with thee, and with thy children after thee;
that they and theirs might enjoy temporal mercies, and continue in the land of Canaan, and partake of all the blessings in it, as follows, and of the sanctuary of the Lord, and the privileges of it:

and that thou mayest prolong thy days upon the earth, which the Lord
thy God giveth thee for ever;
that is, that they and theirs might live long in the land of Canaan, which the Lord gave for an inheritance for ever, provided they kept his law, and were obedient to his commands; see ( Deuteronomy 6:25 ) ( Isaiah 1:19 ) , and though they have had several interruptions by their captivities, and especially by their present very long one, yet when they shall return and seek the Lord their God, and David their king, they shall have their land restored to them again, and shall never more be dispossessed of it.