1 John 4:16

He does not express the divine essence, but wishing to declare the majesty of God, he has applied to the Divinity what is best and most excellent in the view of men. Thus also Paul, when he speaks of "light inaccessible." [1 Timothy 6:16] But John himself also in this same Epistle says, "God is love:" [1 John 4:16] pointing out the excellences of God, that He is kind and merciful; and because He is light, makes men righteous, according to the advancement of the soul, through charity. God, then, who is ineffable in respect of His substance, is light.

And if "God be love "piety also is love: "there is no fear in love; but perfect love casteth out fear.".
It is not, then, without reason that we commanded boys to kiss their relations, holding them by the ears; indicating this, that the feeling of love is engendered by hearing. And "God "who is known to those who love, "is love"

The word of the blessed Apostle John is: "God "saith he, "is love; and he that dwelleth in love dwelleth in God, and God dwelleth in him.".
Also in the Epistle of John: "God is love l and he that dwelleth in love dwelleth in God, and God in him."

Those who have refused to be of one mind in the church of God cannot abide with God.

If God is love, as John says, then it must be that the devil is hatred. As he who has love has God, so he who has hatred has the devil dwelling in him.

"And we have known and believed the love which God hath in us." And again, by what hast thou come to know this? "Love is God." He hath already said it above, behold he saith it again. Love could not be more exceedingly commended to thee than that it should be called God. Haply thou wast ready to despise a gift of God. And dost thou despise God? "Love is God: and he that dwelleth in love dwelleth in God, and God dwelleth in him." Each mutually inhabiteth the other; He that holdeth, and he that is holden. Thou dwellest in God, but that thou mayest be holden: God inhabiteth thee, but that He may hold thee, lest thou fall. Lest haply thou imagine that thou becomest an house of God in such sort as thine house supports thy flesh: if the house in which thou art withdraw itself from under thee, thou fallest; but if thou withdraw thyself, God falleth not. When thou forsakest Him, He is none the less; when thou hast returned unto Him, He is none the greater. Thou art healed, on Him thou wilt bestow nothing; thou art made clean, thou art new-made, thou art set right: He is a medicine to the unhealthy, is a rule for the crooked, is light for the bedarkened, is an habitation for the deserted. All therefore is conferred on thee: see thou imagine not that ought is conferred upon God by thy coming unto Him: no, not so much as a slave.

When we come to the subject of love, which is what God is called in Scripture, the Trinity begins to dawn a little, for there is the Lover, the Beloved and Love.

The Holy Spirit is commonly shared in some way between the Father and the Son. But this communion is itself consubstantial and coeternal. If it can appropriately be described as friendship, let it be so called—but it is better to call it love. It is a substance, because God is a substance, and God is love.

God is love. He already said that above, behold he says it again. Love could not be commended to you more than by saying God. Perhaps you were going to scorn the gift of God: will you scorn God as well?

And he who abides in love, abides in God, and God in him. Conversely, those who contain and those who are contained live in each other. You dwell in God, but so that you may be contained; God dwells in you, but so that He may contain you lest you fall, because as the Apostle says of love itself: Charity never fails. How does he fall whom God contains?

And we have known and believed the love that God has in us. We have known that Jesus is the Son of God, and that the Father sent him as the Savior of the world. And we believe the love that God has in us, because evidently when He had His only Son, He did not want Him to be alone, but so that He might have brothers, He adopted those who would possess eternal life with Him.

There is no Scripture which calls God only love, but John says this in order that we might seek him who is love, from whom the commandment to show mercy came.

Whoever confesses that Jesus is the Son of God, God abides in him, and he in God. And we have known and believed the love that God has for us. God is love, and he who abides in love abides in God, and God in him. In this, love is made perfect with us, so that we may have confidence on the day of judgment, because as he is, so are we in this world.
This refers to what has been said a little earlier, namely that every spirit that confesses Jesus Christ has come in the flesh is from God. (1 Jn. 4:2) For John has sufficiently demonstrated that they are children of God and that God abides in them: this has been demonstrated through great love, which confirms that the Holy Spirit or spiritual gifts have been given to them: again, he refers to those words and says: "Whoever confesses that Jesus is the Son of God, God abides in him;" saying something of this kind: John said above, Everyone who confesses that Jesus Christ has come in the flesh is from God (1 Jn. 4:2): furthermore, in the course of the conversation, something else was revealed, and therefore he proposed this: that those who confess these things also have the Spirit abiding in themselves, or God and his spiritual gifts, and they themselves abide in God. And this we do not say lightly, but with firm knowledge and faith through mutual love.
But having mentioned love, John also refers to all that he has said about love, attributing great faith to the discourse on love. "In this, love is made perfect." He wishes, he says, for us to be perfect in love, so that we may have confidence on the day of judgment, towards Him who was incarnate: for He himself will be the judge, according to his own statement, where he says: "The Father judges no one, but has given all judgment to the Son." (Jn. 5:22) And that there will be confidence towards him who was incarnate, John signified through what he said in the following, that just as he is, we are in this world, saying this: Since it has been shown before that God abides in us, and we are in God, he says, we attest to the perfection of love for ourselves. Just as he was blameless and pure in the world, he also said: "The ruler of this world is coming, and he has nothing in me (Jn. 14:30):" so also we, John says, will be in the world. For there is and we are placed through άντιχρονιαν (where one time is taken for another time), as is the custom of Scripture. Or it signifies something deeper through this. For John has often said that God is in us and we are in God. If this is indeed the case, He is holy in us, that is, the Leader and Prince of holiness: so we should also refer to him in this world sacredly and purely, dead to the world, always bearing his mortification in the body. (1 Cor. 4:10) Furthermore, he says, living this way, we will have confidence towards him, and we will be without fear then. For the “perfect love6”, (1 Jn. 4:18) through good works, will be far from fear. And he adds this confirmation, namely that “perfect love casts out fear”. What fear? He himself says it is the “fear has torment”: for it happens that someone loves because of fear, lest he be punished: but this fear is not perfect, that is, it is not of perfect love. Having said these things about “perfect love”, he completely convinces that we should love God, for John himself first, he says, “loved us”. However, we must, since he has been the first good beginning for us, strive to repay, as has been said more broadly by us above. However, some have asked how, when David says: "Fear the Lord, all his saints, for nothing is lacking to those who fear him," (Ps. 34:9) he does not say: "perfect love casts out fear." Are the saints of God not perfect in love, to whom it is commanded to “fear”? And we say that there are two kinds of “fear”: one is indeed initial, which also brings with it “torment”, because of the evils perpetrated by oneself: fearing him because he approaches God, and therefore approaching lest he be punished, and this is indeed initial. “Perfect”, freed from such fear, is therefore called holy and endures forever: for "The fear of the Lord is holy," David says, "and endures forever." (Ps. 19:9) Since initial fear is neither holy nor enduring, but ceases to exist in “perfect love”. Who then and for what reason is fear called perfect? It is because, having been perfectly taken into love, it strives and fears that it may lack those things which are fitting for them to do towards the beloved, whom they love intensely.