Genesis 2:17 but of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat  of it you shall surely die.”
Footnotes  2:17 Or when you eat (ESV)
Why does it say “in the day” and yet Adam and Eve didn’t die that day?
As the ESV footnote notes, “in the day” can sometimes simply mean “when” in Hebrew (compare Gen.2:4, Josh.14:11, Jer.7:22). But in this case “in the day” is probably stressing immediacy, because the eating — which caused the effect — was in the day. The day that they eat the fruit they were destined to die.
People speculate about whether this means one of two things:
- that they were made “very good”, but actually already mortal, and had to eat the fruit of the tree of life to stay alive; or
- that there was an actual change from being “very good” to the current state of man — which is not “very good”.
Either way, it doesn’t change greatly the point of the narrative. Adam and Eve were created in a state which is outside our common experience now. Now we only know two states — either sinful and mortal (like us), or sinless, then raised, glorified and now immortal (like Christ). Adam and Eve were created in a ‘grey area’, a situation where they had not yet chosen between sin and obedience.
Why do some people say this means “dying you shall die”?
This is a misunderstanding of a grammatical structure in Hebrew, and other semitic languages, called the infinitive absolute. The verb is repeated to mean “surely”, “certainly”.
The Infinitive Absolute occurs most frequently in immediate connexion with the finite verb of the same stem, in order in various ways to define more accurately or to strengthen the idea of the verb. (Gesenius Hebrew Grammar p.342)
This same structure occurs in Gen. 2:16 too:
Genesis 2:16 And the Lord God commanded the man, saying, “You may surely eat of every tree of the garden” …
Literally “eating you may eat”
And again in many other places including Gen.2:17, 18:10, 18:18, 22:17, 28:22, 1 Samuel 9:6, 24:21, Amos 5:7, 7:17, Hab.2:3, Zech.11:17 etc. And related structures occur in Gen. 20:18, 43:3, 44:28, Jos.17:12, Judges 1:28, 1Sam.20:6, 1Kings 3:26, Job 13:5, Joel 1:7, Amos 9:8 etc.
(Infinitive absolutes can be detected by students using concordances with Strong’s numbering because the same number occurs twice for the same verb.)
The structure is also found in the Septuagint (the Jewish Greek Old Testament) as an example of a semitic construction passing into Jewish usage of Greek . This is also found in the New Testament in the words of Jesus where the Greek text records “with desire I have desired to eat this passover” (Luke 22:15) — even though the author, Luke, was a Gentile.