Jesus knew that the religious leaders assumed they were children of God. He accuses them, touching a sensitive nerve, and they responded just as He knew they would. He tells them that although they were physical descendants of Abraham, he was not their father. They are not of God, because if they were truly the spiritual children of Abraham, then they would repent and obey the truth as Abraham did. Instead, their father was the devil.
They respond by insisting that they were not illegitimate, but were indeed of God. Jesus replies that if they really loved God, they would also love Him. He says the reason why they cannot understand Him is that they cannot stand the truth. Like their father, they are in love with a lie, and they live a life of lies. If you do the truth you will know the truth. They point the finger at Jesus because they have no faith in God. Their faith was in themselves.
Truth becomes less believable when we let lies cloud our soul. If you obey the truth it is because you love the truth, and if you love truth you will hear God. If your love is poisoned with prejudice you will listen to the lies of your father, the devil.