1 John 4:3

That dissolveth Jesus, viz. either by denying his humanity or his divinity. (Challoner) --- This is antichrist; [2] i.e. such is the spirit of antichrist, of whom you have heard that he cometh, or is to come in the latter times. --- And he is now already in the world, not the chief and great antichrist, but his precursors, in whom he may be said to come. (Witham) --- And he is now already in the world. Not in his person, but in his spirit and in his precursors. (Challoner)

[BIBLIOGRAPHY]

Et hic est antichristus, Greek: kai touto (pneuma) to tou antichristou. By the Greek hic cannot agree with the man, and so the construction in Latin must be, hic est ille spiritus antichristi.