Their hatred for Jesus was proof that God wasn't
their Father, they were the children of the devil.

Earlier Jesus had convicted the accusers of the
woman caught in adultery, so that they had left
without any more accusations. But He then said,
"Which of you convinceth me of sin?" John 8:46
Shocked by His rebuke, they couldn't point to any
sin so they said that He was "a Samaritan, and
hast a devil."