The first government that God set up between Himself and man was the Dispensation of Innocence. Adam and Eve were created in innocence and placed in an environment that is described as being "very good". The Lord desired for Adam and Eve and their descendants to have dominion over all the earth (Gen. 1: 26) but He wanted them to remain in a state of innocence. That is why He forbade them to eat of the tree of the knowledge of good and evil:
"And the LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat: But of the tree of the knowledge of good and evil, thou shalt not eat of it" (Gen 2: 16-17).
In their state of innocence Adam and Eve did not know good from evil because they knew only good.
However, Eve was deceived by the serpent and she ate of the forbidden tree:
"And Adam was not deceived, but the woman being deceived was in the transgression" (1 Tim. 2: 14).
The serpent told her that if she ate of the forbidden tree she would "be as God, knowing good and evil":
"For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil. And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat" (Gen. 3: 5-6).
This appealed to Eve’s pride (desirable to make one wise), and when she saw that the tree was "good for food" and "pleasant to the eyes" she decided to go her own way instead of the Lord’s way and she ate of the tree. Although the Scriptures do not say why Adam sinned, we do know that he was not deceived. He ate of the forbidden tree with his eyes wide open. Perhaps he ate of the forbidden tree out of fear of loosing Eve.
Whatever the reason, the "dispensation of innocence" ended when man rebelled against his Creator and now man had the "knowledge of good and evil" written in his heart: "Who show the work of the law written in their hearts, their conscience also bearing witness" (Ro. 2: 15).
Clarence Larkin writes: "Adam and Eve had no conscience before the ‘Fall’. Conscience is a knowledge of ‘Good’ and ‘Evil’, and this Adam and Eve did not have until they had their eyes opened by eating of the ‘Fruit’ of the ‘Tree of the Knowledge of Good and Evil’ "(Larkin, Rightly Dividing The Word, p. 19).
Now all men would be made in the image of Adam who now had the "knowledge of good and evil" written in his heart:
"And Adam lived an hundred and thirty years, and begat a son in his own likeness, and after his image; and called his name Seth" (Gen. 5: 3).