Moses
Deuteronomy 4:6BSB·traditional attribution

Observe them carefully, for this will show your wisdom and understanding in the sight of the peoples, who will hear of all these statutes and say, “Surely this great nation is a wise and understanding people.”

John Calvin Reformed @genevareformer

6. Keep therefore, and do them. In order that they may set themselves more cheerfully about the keeping of the Law, and may proceed more steadily in this endeavor, he reminds them that nothing is better or more desirable for themselves. For God is not duly honored, except with ready minds and volutary obedience, to which we are rather attracted by pleasure than forced by rigor and violence.

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

Keep therefore and do them,..... Observe them, take notice of what is expressed by them, and perform them, both as to matter and manner, as they require: for this is your wisdom and your understanding in the sight of the nations; that is, their wisdom and understanding would appear to other nations by their observance of the commands of God: which hear all these statutes...