4:12 {10} No man hath seen God at any time. If we love one another, God dwelleth in us, and his love is {g} perfected in us.
(10) A third reason: Because God is invisible, therefore by this effect of his Spirit, that is, by charity, he is understood to be not out of us, but united with us and in us, in whom he is so effectually working.
(g) Is surely in us indeed, and in truth.
4:12 No man hath seen God at any time. He is invisible to mortal eyes, yet we may have a sense of his presence in us. If we love each other he dwells in us.
His love is perfected in us. It is made complete by our loving each other. It is incomplete unless his love for us is supplemented by brotherly love. This love in us is the proof that God is in us.
4:12 If we love one another, God abideth in us - This is treated of, 1John 4:13 - 16. And his love is perfected - Has its full effect. In us - This is treated of, 1John 4:17 - 19.
4:7-13 The Spirit of God is the Spirit of love. He that does not love the image of God in his people, has no saving knowledge of God. For it is God's nature to be kind, and to give happiness. The law of God is love; and all would have been perfectly happy, had all obeyed it. The provision of the gospel, for the forgiveness of sin, and the salvation of sinners, consistently with God's glory and justice, shows that God is love. Mystery and darkness rest upon many things yet. God has so shown himself to be love, that we cannot come short of eternal happiness, unless through unbelief and impenitence, although strict justice would condemn us to hopeless misery, because we break our Creator's laws. None of our words or thoughts can do justice to the free, astonishing love of a holy God towards sinners, who could not profit or harm him, whom he might justly crush in a moment, and whose deserving of his vengeance was shown in the method by which they were saved, though he could by his almighty Word have created other worlds, with more perfect beings, if he had seen fit. Search we the whole universe for love in its most glorious displays? It is to be found in the person and the cross of Christ. Does love exist between God and sinners? Here was the origin, not that we loved God, but that he freely loved us. His love could not be designed to be fruitless upon us, and when its proper end and issue are gained and produced, it may be said to be perfected. So faith is perfected by its works. Thus it will appear that God dwells in us by his new-creating Spirit. A loving Christian is a perfect Christian; set him to any good duty, and he is perfect to it, he is expert at it. Love oils the wheels of his affections, and sets him on that which is helpful to his brethren. A man that goes about a business with ill will, always does it badly. That God dwells in us and we in him, were words too high for mortals to use, had not God put them before us. But how may it be known whether the testimony to this does proceed from the Holy Ghost? Those who are truly persuaded that they are the sons of God, cannot but call him Abba, Father. From love to him, they hate sin, and whatever disagrees with his will, and they have a sound and hearty desire to do his will. Such testimony is the testimony of the Holy Ghost.