Man was a responsible creature before he fell. Distrust of God and lust were instilled into the soul of the woman. Will was put forth against God, and in the case of Adam it was high-handed will, for he was not deceived (1 Tim. 2:14), and man fell. A breach as wide as the poles came in at once between God and man, an abyss impossible to repair or re-cross. "Man is become as one of Us," said the Lord, "to know good and evil." Gen. 3:22. This he never can unlearn; he never returns to innocence again.
What then is "to know good and evil"? It is something which is said of the Godhead too; "as one of Us, to know good and evil." It is to sit in judgment and pass sentence on good or evil which we find in our own souls. Of David the king it was said by a wise woman of Tekoah, "as an angel of God, so is my lord the king to discern good and bad." 2 Sam. 14:17. This is in reference to the decisions of judgment. So also it is of Solomon in 1 Kings 3:9, and of Israel in Deuteronomy 1:39 and Heb. 5:14.
This is the work of conscience, first to take knowledge of the evil practiced by a will opposed to God, to sit in judgment upon it and to condemn, and second, to apprehend the good while opposed to it and to approve of it without the power to perform. This was fallen man with a conscience; he was responsible before he fell, distrusting God and willfully transgressing His command. He possessed an ability, even when fallen, to pass sentence upon his own actions by the knowledge of good and evil. He recognized good that he had not the power nor desire to practice, and evil that he was not able to avoid!
Then at last he was driven out of the presence of God, for he had lost his place on such ground forever. These three things marked his state: (1) Distrust of God. (2) Sin committed in that distrust. (3) His place irrecoverably lost.
These three things are reversed by the gospel. His confidence is restored by faith in Him as the Savior; his sins are removed which had been committed in distrust and he is brought into a new place in Christ before Him.