פּירוש אויף בראשית 2:17

For on the day you eat from it, you will certainly die: Meaning to say, know that your end will be to die. You will certainly die, such that you will not be saved from death at the time of [your] end. But He did not say that he would die on that day.

כי ביום אכלך ממנו מות תמות, “for on the day youwould eat from it you would surely become mortal.” Man had not been created as a mortal body, but after having sinned he was punished by becoming mortal. G-d’s warning did not mean that he would die immediately. He only had warned him that he would lose his entitlement to infinite life. At some time in the future he would not be able to escape the need to die. This is why he had to be separated from proximity to the tree of life, so that he could not regain the immortality that he had now lost.

THOU SHALT NOT EAT OF IT. He admonishes him against eating the fruit, for the tree itself is not edible. And so it says further on: But of the fruit of the tree which is in the midst of the garden.³²⁸Genesis 3:3. Similarly, And eat ye every one of his vine, and every one of his fig tree³⁴⁸II Kings 18:31. [means “of the fruit of his vine and of the fruit of his fig-tree].” Likewise, In toil shalt thou eat it³⁴⁹Genesis 3:17. means “eat its fruit.”