Here the apostle continues the practical application of the doctrine of redemption, which he had started in verse 13. We have already seen in our previous studies of this Epistle, that the grand design of the apostle is to unfold before these persecuted Christians the great redemption, which the Lord wrought for them. His intent, in doing so, is to strengthen, encourage, assure and comfort these Christian people, whose faith was sorely tried by persecution at this time. But redemption and holiness go together, and they cannot be divided or divorced. Indeed, we are redeemed to the end that we may be holy.

Now, having outlined in the previous verses, the whole duty and frame of the Christian life in general toward God and man, he, in these verses, specifies this particular duty of mutual Christian love toward one another.

Three things are brought forth here: (a) the Christian duty enjoined; (b) the nature of it; and (c) the reasons for it.

A.  The Christian duty enjoined – brotherly love⤒🔗

The very first thing that must be observed is that the love that is spoken of here does not come naturally to men. By nature we all "are prone to hate God and our neighbour". But even in the renewed nature of the Christian it does not naturally develop. It must be earnestly sought for and diligently cultivated. It is the result of the sanctifying work of the Holy Spirit.

Now, the love that is enjoined here as a Christian duty is "love of the brethren". This does not mean that the Christian may be indifferent, or apathetic, much less unloving to the rest of the human race. There is a love which we owe to every man as man – a sincere desire to promote his true welfare. To quote again the oft-cited Leighton:

''Where a godly man sees his Father's image, he is forced to love it; he loves those whom he perceives godly, so as to delight in them, because that image is in them; and those that appear destitute of it, he loves them so as to wish them partakers of that image, … he loves a friend in God, and an enemy of God''.

But he loves the brethren with a love of complacency as those of the same household of faith in whom he sees "his Father's image". It is the love whereby the Christian desires the good and happiness of the brethren, sympathizing with their griefs, desiring and endeavouring to help; bearing their infirmities; raising them when they fall; admonishing and reproving them as is needful, sometimes sharply and yet still in love; rejoicing in their good; and far from envying, he rather delights in and is glad for their gifts and graces as if they were his own.

This, says Leighton, the Lord gave to His disciples "as the very badge and livery" by which they should be known as His followers. "By this shall all men know that you are my disciples, if ye love one another" (John 13:35). Paul calls it "the bond of perfectness" (Col. 3:14). It is the grace that unites and binds us together. "See," said the pagan world of the early Christians, "see how these Christians love one another!" One may go constantly to church, he may pray in public and in private, he may do all his religious duties diligently, but if he cannot find it in his heart to love the brethren and to forgive an injury, by this he may know that he is none of His.

B.  The nature of brotherly love←⤒🔗

But how can one know if he has this grace? We live in days in which nothing is more talked about, but nothing is less known, exercised and evidences itself as this Christian virtue of brotherly love. And those who speak of it most, often are most destitute of it in their lives. What is this brotherly love? What are its distinguishing characteristics? How may we discern its presence?

True Christian love – the fruit of the Spirt – is, in the first place, sincere; "unfeigned love" says Peter. The word used here is the same that Paul uses in Romans 12:9, where it is translated "without dissimulation". It can be properly translated "without hypocrisy". It is what John says, "to love not in word, neither in tongue; but in deed and in truth" (1 John 3:18), knowing that "although thy brother, with whom thou conversest, cannot it may be see through the false appear­ances, He who commands this love looks chiefly within, seeks it there, and, if he find it not there, hates them most who pretend it; so that the art of dissembling, though never so well studied, cannot pass in this King's court, to whom all hearts are open, and all desires known" (Leighton).

Secondly, the Christian love is pure – "love one another with a pure heart". This is not the same as the previous one. Indeed, it is true that every hypocrisy and dissimulation is impurity, but it is also true that one may sincerely unite with another into a fraternity of iniquity.

By "love with a pure heart" is meant: negatively, freedom from all low and selfish motives, and positively, it "signifies the benevolent affection that naturally flows from a sanctified heart" (J. Brown). It is the love that springs from the very nature of their being, for they all are united with Christ their Head, and with one another in Christ as members of the one body of our Lord. They love each other for Christ's sake and in a Christ-like manner, for He says: "A new commandment give I you, that as I have loved you, that you likewise should love one another" (John 13:34).

Thirdly, true Christian love must be fervent. "Love one another with a pure heart fervently"; not in a cold and indifferent manner, but with a love that burns like a fire within you, "consuming that selfishness" and ablazing you to holy affection toward the brethren.

The term used here, which is translated "fervently", is a very expressive one, and not one English word will do justice to it. It conveys the idea of constancy. It is the same word as that in Acts 12:5, where it is said that "prayer was made without ceasing of the church unto God for Peter" who was cast into prison. Brotherly love must be exercised not in fits and starts, but one must live in the conscious exercise of it towards all the brethren, at all times, under all circumstances. In the words of J. Brown, "A Christian brother, when he acts like himself, loves at all times! No change of circumstances, especially to the worse on the part of its object, should affect it except in the way of increasing it".

But it also conveys the idea of intensity and power. It is the term employed when it is said that our Lord "being in agony, prayed more earnestly" (Luke 22:44). Our Christian love should be strong and earnest as well as genuine. Slight causes should not be able to destroy it, or materially to affect it, and sacrifices that we may be called upon to make should not be able to exhaust it.

C.  Reasons commending brotherly love←⤒🔗

The apostle cites two reasons why Christians should love one another unfeignedly, with a pure heart, fervently.

The first of these is their common origin and the conse­quent mutual relationship. They are "being born again".

This is the second time that the apostle mentions regen­eration. In verse 3 he had developed the doctrine of regeneration: God "according to his abundant mercy hath begotten us again unto a lively hope by the resurrection of Jesus Christ from the dead". Christians are not ordinary people, they are new creatures – born again! Moreover, they "are born not of blood, nor of the will of the flesh, nor of the will of men, but of God" (John 1:13). They are the blood-royal of heaven, "being born again not of corruptible seed, but of incorruptible, by the word of God", through the Holy Spirit. This is their dignity and it is true of every Christian. This is the doctrine of regeneration. A Christian is not someone who is born so, or who has become, or is made so, by baptism. A Christian is a man who has experienced the mighty renewing work of the Holy Spirit in his heart.

But now the apostle refers to it again to show the application of it. Because you are born again, because you are renewed by the Spirit of God, therefore love the brethren with a pure heart fervently. The natural man cannot love; it is contrary to his nature. By nature he is "prone to hate God and his neighbour", but to do good he knows not. The love of the brethren, therefore, is at once the cause and the evidence of the new nature in the soul of man.

The Christian loves the brethren because the love of God is shed abroad in their hearts, and because of their intimate, indissoluble, mutual relationship established among them rising out of their intimate common relationship to God as their Father. There is the same blood running in their veins; washed by the same precious blood of Christ, they have the same Father, the same Spirit, within them and the same Lord Jesus Christ, the Head of this glorious fraternity.

And the apostle gives a second reason why they should love one another with unfeigned love out of a pure heart. They must do so, not only because they are brothers, but also because they now are in a moral capacity to love the brethren. Their whole nature and character has been changed, has been transformed by the sanctifying work of the Holy Spirit. Their souls are "purified in obeying the truth through the Spirit unto unfeigned love of the brethren". As it is impossible for the natural man to love, so it is quite unnatural for the spiritual man not to love the brethren.

This whole article, by the very nature of it, has been practical. Therefore, very little can be added by way of application. Perhaps the best way of applying it is by suggesting some heart-searching questions to ourselves. Do we love the brethren with a pure heart fervently? Do we love them on account of their relation to God and to the Lord Jesus Christ? Is our delight in them, as "the excellent ones of the earth" (Psalm 16:3)? Have we pleasure in their society? Do we endeavour by all means to promote their welfare? Can we answer these questions in the affirmative by the grace of God, the Spirit also bearing witness within us that our delight is in them? The question is a very important and urgent one because by this not only the world "shall know that we are Christ's disciples, if we love one another", but we ourselves also "know that we are passed from death to life, because we love the brethren. He that loveth not his brother abideth in death" (1 John 3:14). For "if a man say, I love God, and hateth his brother, he is a liar; for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen?" (1 John 4:20). Oh, how little of this love there is among brethren! How much strife and contention, backbiting and slander there is in the churches! Why so? "The true reason," says Leighton, "why there is so little truth of this Christian mutual love amongst those that are called Christians is because there is so little of this purifying obedience to the truth whence it flows. Faith unfeigned would beget this love unfeigned. Men may exhort to them both, but they require the hand of God to work them in the heart".

Finally, let us manifest our love "not in word and tongue only, but in need and in truth". "With all lowliness and meekness, with long-suffering, forbearing one another in love; endeavouring to keep the unity of the Spirit in the bond of peace" (Eph. 4:2-3). "Let all bitterness, and wrath, and anger, and clamor, and evil speaking, be put away from us, with all malice," "and above all these put on charity (love), which is the bond of perfectness" (Eph. 4:31, Col. 3:14).