You do know this particular fable is not in the earliest manuscripts? Neither is it on the earliest version of the New Testament?"Now Moses in the law commanded us, that such should be stoned: but what sayest thou? 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. 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. "
Like much of the Bible, it was added many years later. Another example of the theological gerrymandering that led to the Bible you use today.