“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 speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.”
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 speaketh a lie, he speaketh of his own: for he is a liar, and the father of it — Jesus names the true father of those who oppose him: the devil (diabolos). The devil is characterized as 'a murderer from the beginning' (ek tēs archēs, from the creation), having refused to stand in the truth. When the devil speaks lies, he 'speaks of his own' (ek tōn idiōn)—lies originate in his nature. He is 'the father of it' (the father of lying). The characterization establishes that opposition to Jesus through lies and murder flows from the devil's nature being worked through human agents.
Church Fathers on John 8:44
Our Lord, having already cut off the Jews from relationship to Abraham, overthrows now this far greater claim, to call God their Father, You are of your father the devil.
Here we must guard against the heresy of the Manicheans, who hold a certain original nature of evil, and a nation of darkness with princes at their head, whence the devil derives his existence. And thence they say our flesh is produced; and in this way interpret our Lord’s speech, You are of your father the devil: viz. to mean that they were by nature evil, drawing their origin from the opposite seed of darkness.
And this seems to be the same mistake, as if one said, that an eye which saw right was different in kind from an eye which saw wrong. For just as in these there is no difference of kind, only one of them for some reason sees wrong; so, in the other case, whether a man receives a doctrine, or whether he does not, he is of the same nature.