John Gill emphasizes the profound love of God in adopting believers as His children, urging them to live holy lives and practice brotherly love. He explains that this adoption is a gift of grace, not based on merit, and highlights the distinction between the children of God and the children of the devil. Gill encourages believers to recognize their identity as sons of God, which should inspire purity and love, despite the world's inability to understand or accept them. He draws parallels between the love of Christ and the call for believers to love one another sacrificially, reinforcing that true love is evidenced by actions, not mere words.

INTRODUCTION TO 1 JOHN 3 In this chapter the apostle exhorts to a holy life and conversation in general, and to the exercise of brotherly love in particular. The former of these is urged from the consideration of the great blessing of adoption, which springs from the free love and favour of God, is unknown to the men of the world, and indeed, in the present state of things, does not appear to the saints themselves in all its fulness and advantages, as it will do in the future state, when the children of God will be like to Christ, and see him as he is; the hope of which should engage them to purity of life and conversation, 1Jo 3:1, and this is further enforced from the nature of sin, which is a transgression of the law, 1Jo 3:4, from the end of Christ's manifestation in the flesh, which was to take away sin, and who was without it, 1Jo 3:5, from communion with Christ, expressed by abiding in him, seeing and knowing him, which such must be strangers to that live a sinful course of life, 1Jo 3:6, from this, that only such that do righteousness are righteous persons, and these are righteous as Christ is, 1Jo 3:7, and from a man's being of the devil, that is, of a vicious conversation, who was a sinner from the beginning, and whose works Christ was manifested in the flesh to destroy, 1Jo 3:8, and from the nature of the new man, or that which is born of God, which is not to sin, nor can it, 1Jo 3:9, and from the distinction there is between the children of God and the children of the devil, those not being of God who do not righteousness, nor love their brethren, 1Jo 3:10, from hence the apostle passes to brotherly love, and excites and engages to that, from its being a message which had been heard from the beginning, 1Jo 3:11, which is illustrated by its contrary in the instance of Cain, who by the instigation of Satan slew his brother, because his works were righteous, and his own were evil, 1Jo 3:12, wherefore, it is no wonder that good men should be hated by the world, who, as Cain, are of the same wicked one, 1Jo 3:13, brotherly love is further urged unto, from its being an evidence of passing from death to life, or of regeneration; whereas he that hates his brother openly continues in a state of death, is a murderer, and so has not eternal life abiding in him, 1Jo 3:14, and from the great instance of Christ's love, in laying down his life for his people, the saints are incited to lay down their lives for one another; to such a pitch does the apostle carry brotherly love, 1Jo 3:16, wherefore, he that is rich, and is uncompassionate to his brother in distress, cannot be thought to have the love of God dwelling in him, 1Jo 3:17, hence he presses the exhortation to brotherly love, that it be not in profession only, but true, real, and cordial, 1Jo 3:18, and that by observing the advantages of it, as that hereby men know they are of the truth, and can assure their hearts before God; and which is illustrated by the contrary, the condemnation of the heart, 1Jo 3:19, the advantages of non-condemnation of the heart are confidence before God, and receiving whatsoever we ask of him; the reason of which is, because his commandments are kept, and things done which are pleasing to him, 1Jo 3:21, the commandments are explained of faith in Christ, and love to one another, 1Jo 3:23, and the happiness of them that do them is, that Christ dwells in them, and they in him, the evidence of which is, the Spirit that is given unto them, 1Jo 3:24. Ver. 1. Behold what manner of love,.... See, take notice, consider, look by faith, with wonder and astonishment, and observe how great a favour, what an instance of matchless love, what a wonderful blessing of grace, the Father hath bestowed upon us: the Father of Christ, and the Father of us in Christ, who hath adopted us into his family, and regenerated us by his grace, and hath freely given us the new name: that we should be called the sons of God. The Alexandrian copy, and some others, and the Vulgate Latin version, add, "and we are", or "be"; and the Ethiopic version, "and have been"; for it is not a mere name that is bestowed, but the thing itself in reality; and in the Hebrew language, "to be called", and "to be", are terms synonymous; see Isa 9:6; in what sense the saints are the sons of God; See Gill on "Ga 4:6"; this blessing comes not by nature, nor by merit, but by grace, the grace of adoption; which is of persons unto an inheritance they have no legal right unto; the spring of it is the everlasting and unchangeable love of God, for there was no need on the adopter's side, he having an only begotten and beloved Son, and no worth and loveliness in the adopted, they being by nature children of wrath; it is a privilege that exceeds all others, and is attended with many; so that it is no wonder the apostle breaks out in this pathetic manner, and calls upon the saints to view it with admiration and thankfulness: therefore the world knoweth us not; that is, the greater part of the world, the world that lies in wickedness, the men of the world, who have their portion in this life, whom the god of this world has blinded, and who only mind the things of the world, and are as when they came into it, and have their conversation according to the course of it; these do not know the saints are the sons of God; the new name of sons is what no man knoweth but he that receiveth it; they do not own the saints as theirs, as belonging to them, but reckon them as the faith of the world, and the offscouring of all things; nor do they love them, and that because they are not their own, but hate them and persecute them: the reason is, because it knew him not; neither the Father, whose sons they are, and who has bestowed the grace upon them; wherefore they know not, and disown and persecute his children; see Joh 17:25; nor the Lord Jesus Christ, the only begotten of the Father, the firstborn among many brethren; who, though he made the world, and was in it, was not known by it, but was hated, abused, and persecuted; and therefore it need not seem strange that the saints, who are the sons of God by adoption, should be treated in like manner.