Ah - here's where we ignore the old testament.
8:5 Now Moses in the law commanded us, that such should be stoned: but what sayest thou?
8:6 This they said, tempting him, that they might have to accuse him. But Jesus stooped down, and with his finger wrote on the ground, as though he heard them not.
8:7 So when they continued asking him, he lifted up himself, and said unto them, He that is without sin among you, let him first cast a stone at her.
So how much of the old testament is now obsolete?
The ten commandments?