Moses
Deuteronomy 4:40ESV·traditional attribution

Therefore you shall keep his statutes and his commandments, which I command you today, that it may go well with you and with your children after you, and that you may prolong your days in the land that the LORD your God is giving you for all time.”

Matthew Henry Presbyterian @wholebiblehenry

This most lively and excellent discourse is so entire, and the particulars of it are so often repeated, that we must take it altogether in the exposition of it, and endeavour to digest it into proper heads, for we cannot divide it into paragraphs. I.

Commenting on Deuteronomy 4:1-40

John Gill Reformed Baptist @doctorgill

Thou shall keep therefore his statutes, and his commandments,.... 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...

Geneva Bible Notes Reformed @genevanotes

Thou shalt keep therefore his statutes, and his commandments, which I command thee this day, that it may go well with thee, and with thy children after thee, and that thou mayest prolong [thy] days upon the earth, which the LORD thy God giveth thee, for ever. (b) God promises reward not for our merits, but to encourage us, and to assure us that our labour will not be lost.