"Ye are of your father the devil, and the lusts
of your father ye will do. He was a murderer
from the beginning, and abode not in the truth,
because there is no truth in him. When he speak-
eth a lie, he speaketh of his own: for he is a liar,
and the father of it." John 8:44

Jesus made this statement that deeply hurt their
pride. They (the Jews) boasted about being the
seed of Abraham and heirs to the promise. Jesus
recognized that yes they were but after the flesh,
not of faith which really mattered.