For just as through the disobedience of the one man the many were constituted sinners, thus also through the obedience of the one [man], the many are constituted righteous (Romans 5:19).
Adam disobeyed God. He was not deceived when he chose to eat from the tree of the knowledge of good and evil (that which is beneficial and that which brings calamity) (1 Timothy 2:14). His disobedience constituted all men as sinners. In an innocent state—not knowing good and evil—Adam chose to reject God’s guidance and sought to determine for himself what was beneficial in the situation he faced, due to Eve partaking of the forbidden tree after having been thoroughly deceived. This resulted in a direct defiance of God’s command to him.
Christ, facing the death of the cross, cried out to the Father, asking Him to save Him from this death. Although it was His desire that the cup be taken from Him, He chose to submit in obedience to the Father’s will, thus fulfilling all righteousness (Mark 14:36). Just as Adam’s disobedience constituted all as sinners, so through Christ’s obedience, many are constituted as righteous.