10 These things are now manifest, my brethren. Let no man say, I do not worship Christ, but I worship God His Father. “Every one that denies the Son, has neither the Son nor the Father; and he that confesses the Son, has both the Son and the Father.” He speaks to you that are grain: and let those who were chaff, hear, and become grain. Let each one, looking well to his own conscience, if he be a lover of the world, be changed; let him become a lover of Christ, that he be not an antichrist. If one shall tell him that he is an antichrist, he is angry, he thinks it a wrong done to him; perchance, if he is told by him that strives with him that he is an antichrist, he threatens an action at law. Christ says to him, Be patient; if you have been falsely spoken of, rejoice with me, because I also am falsely spoken of by the antichrists: but if you are truly spoken of, come to an understanding with your own conscience; and if you fear to be called this, fear more to be it.
Source: Homilies on the First Epistle of John (New Advent)