God promises Adam and Eve that they will die "in that day" they eat from the tree of the knowledge of good and evil.
Genesis 2:16-17, Old Testament, The Church of Jesus Christ of Latter-Day Saints, accessed September 27, 2022
16 And the Lord God commanded the man, saying, Of every tree of the garden thou mayest freely eat:
17 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.