Kommentar zu Bereschit 3:19

בזעת אפיך IN THE SWEAT OF THY FACE — after you have taken all this great trouble.

By the sweat of your face, you shall eat bread: There is support from here for the words of the physicians who say that before eating anything, a person should engage in some work that warms up [the eater], since this helps digestion. And it is as it is written (Psalms 128:2), "For you shall eat the labor of your hands; happy shall you be, and it shall be well with you." That which Scripture states (Genesis 13:17), "With itzavon you shall eat from it all the days of your life," is because itzavon is an expression of work, as it is stated in Job (10:8), "Your hands have made me (itzvoni) and fashioned me." And its saying, "all the days of your life," is to teach that he should eat uniquely for the sake of his life, and not seek luxuries. As what is the benefit of working for emptiness?

אל עפר תשוב, you will revert to dust, just as I had told you “on the day you eat from it you will surely become mortal.” (not that he would actually die on that same day).