Charles Ellicott Commentary Genesis 2:16-17

"And Jehovah God commanded the man, saying, Of every tree of the garden thou mayest freely eat: but of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die." — Genesis 2:16-17 (ASV)

The Lord God commanded. —Probation is the law of man’s moral condition now, and it began in Paradise, only the conditions there were different. (See Excursus at the end of this book.)

In the day... . —This phrase is used, as in Genesis 2:4, for an indefinitely long period. But just as on the third day God gave the whole law of vegetation, though trees, as the highest development of that law, may not have been reached until after the appearance of animal life on the earth, so the law of man’s mortal life came into existence with the eating of the forbidden fruit. Contemporaneously with that act, man passed from the paradisiacal state, with the possibility of living forever, into the mortal state, with the certainty of sooner or later dying.

It was a new condition and fundamental nature of things that then commenced, and to which not only Adam but also his posterity was subject. And thus this command resembles the words of Elohim in the first chapter. By them, the fundamental laws of the material universe were given and established for all time; and the word of Jehovah-Elohim was equally a law here, not only for the day on which Adam broke the command, but for all people everywhere as long as the world lasts.