When the crowd pickedup their stones to throw at the prostitute Jesus said let the first man here w/o sin throw the first stone.
This not overturning God's established laws, only changing who should enforce them. Jesus didn't say it's morally wrong to stone a prostitute, he only put the spotlight on the hypocrisy of people who wanted to stone her.
The problem I see with this passage is that Jesus didn't obey his Father (also himself), because Jesus was apparently without sin, so should've obeyed himself and chucked the first rock himself. He actually invited anyone without sin to chuck away - but didn't do it himself. I wonder what sin Jesus had committed that excluded himself from righteous rock chucking - by his own standards?