All throughout the New Testament we are educated as to the moral standards God wants mankind to have. God in His infinite wisdom told us how we should live.
But the fruit of the Spirit is love, joy, peace,
kindness, goodness, faithfulness, gentleness, self-control. Against
such there is no law. Galatians 5:22-23
In each culture, we see evidence of God's moral law. Murder is against the law as is thievery and many other rules of our Lord.
You have heard that it was said to those of
old,"You shall not
murder, and whoever murders will be in danger of the judgment."
But I say to you that whoever is angry with his brother without a cause
shall be in danger of the judgment. And whoever says to his brother,
"Raca!" shall be in danger of the council. But whoever says, "You
fool!" shall be in danger of hell fire. Matthew 5:21-22