'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.

and every spirit that does not confess Jesus [acknowledging that He has come in the flesh, but would deny any of the Son’s true nature] is not of God; this is the spirit of the antichrist, which you have heard is coming, and is now already in the world.