'Acknowledge' in the Bible

Who is the liar but the one who denies that Jesus is the Christ (the Messiah, the Anointed)? This is the antichrist [the enemy and antagonist of Christ], the one who denies and consistently refuses to acknowledge the Father and the Son.

See what an incredible quality of love the Father has shown to us, that we would [be permitted to] be named and called and counted the children of God! And so we are! For this reason the world does not know us, because it did not know Him.

But every spirit who does not acknowledge Jesus is not from God. This is the spirit of the antichrist. You have heard that he is coming, and now he is already in the world.