Jesus himself told the Adulteress to go and sin no more. He died for our sins, not for our faith.
Yes He did. And when we come to Him he says the same to us! But any action short of faith is SIN. Without faith it is IMPOSSIBLE to please God. And only with faith can one be able to go and sin no more, but if we do, we have an advocate before God on our behalf. And without faith we might not outwardly commit adultery we are what what Jesus called whitewashed tombs, pretty and clean on the outside, but inside full of corruption.
Telling the culture about morality will never change the culture. God himself gave the rules of morality to Israel and they couldn't be what He wanted them to be. Only when the law of God is written on our heart are we able to begin to behave with Godly morality.
Galatians 2:
16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified.
17 But if, while we seek to be justified by Christ, we ourselves also are found sinners, is therefore Christ the minister of sin? God forbid.
18 For if I build again the things which I destroyed, I make myself a transgressor.
19 For I through the law am dead to the law, that I might live unto God.
20 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.
21 I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain.