9 Now therefore, brethren, if deeds are to be questioned, not only do we find many antichrists gone out; but many not yet maninfest, who have not gone out at all. For as many as the Church has within it that are perjured, defrauders, addicted to black arts, consulters of fortune-tellers, adulterers, drunkards, usurers, boy-stealers, and all the other vices that we are not able to enumerate; these things are contrary to the doctrine of Christ, are contrary to the word of God.
Now the Word of God is Christ: whatever is contrary to the Word of God is in Antichrist. For Antichrist means, “contrary to Christ.” And would ye know how openly these resist Christ? Sometimes it happens that they do some evil, and one begins to reprove them; because they dare not blaspheme Christ, they blaspheme His ministers by whom they are reproved: but if you show them that you speak Christ's words, not your own, they endeavor all they can to convict you of speaking your own words, not Christ's: if however it is manifest that you speak Christ's words, they go even against Christ, they begin to find fault with Christ: “How,” say they, “and why did He make us such as we are?”
Do not persons say this every day, when they are convicted of their deeds? Perverted by a depraved will, they accuse their Maker. Their Maker cries to them from heaven, (for the same made us, who new-made us:) What made I you? I made man, not avarice; I made man, not robbery; I made man, not adultery. You have heard that my works praise me. Out of the mouth of the Three Children, it was the hymn itself that kept them from the fires. The works of the Lord praise the Lord, the heaven, the earth, the sea, praise Him; praise Him all things that are in the heaven, praise Him angels, praise Him stars, praise Him lights, praise Him whatever swims, whatever flies, whatever walks, whatever creeps; all these praise the Lord.
Have you heard there that avarice praises the Lord? Have you heard that drunkenness praises the Lord? That luxury praises, that frivolity praises Him? Whatever you hear not in that hymn give praise to the Lord, the Lord made not that thing. Correct what you have made, that what God made in you may be saved. But if you will not, and lovest and embracest your sins, you are contrary to Christ. Be thou within, be thou without, you are an antichrist; be thou within, be thou without, you are chaff. But why are you not without? Because you have not fallen in with a wind to carry you away.
Source: Homilies on the First Epistle of John (New Advent)