“The knowledge of good and evil”
but you must not eat from the tree of the knowledge of good and evil; for in the day that you eat of it, you will surely die. (Genesis 2:17 BSB)
What it sounds like today
A tree that magically imparts the ability to tell right from wrong.
The cultural key
'Knowledge of good and evil' is easily misread as simply learning to tell right from wrong, but the phrase is a Hebrew merism: naming two opposites ('good and evil,' like 'heaven and earth' or 'young and old') to mean the entire span between them, that is, everything. So the tree offers not moral awareness but total, comprehensive knowledge, and specifically the authority to determine good and evil, to be the one who decides what is right, a prerogative that belongs to God. The serpent's promise, 'you will be like God, knowing good and evil' (3:5), confirms the sense: the temptation is not to gain a conscience but to seize God's role as the definer of right and wrong, moral autonomy from the Creator. Read as a magic morality tree it is puzzling; read as the merism it is, it is the reach for godlike self-rule.
Recovered meaning
'Good and evil' is a merism for the whole of knowledge, so the phrase means the godlike right to decide right and wrong for oneself. The temptation is not gaining a conscience but seizing God's role as the definer of good and evil.