When he comes to the fifth chapter in his Commentary on Galatians (i.e. the imperatival section of the book), Martin Luther carefully explained the language of “faith working through love”–as it is found in Galatians 5:6. Note how carefully Luther defines the relationship between faith that justifies apart from anything we do, and how that faith then goes on to work through love unto sanctified living:
“For in Jesus Christ neither circumcision avails any thing, neither uncircumcision, but faith which works by love” (Gal. 5:6).
That is to say, faith which is not feigned nor hypocritical, but true and lively. This is that faith which exercises and requires good works through love. It is as much as to say, he that will be a true Christian indeed, or one of Christ’s kingdom, must be a true believer. Now he does not truly believe, if works of charity do not follow his faith. So on both hands, as well on the right hand as on the left, he [i.e. Paul] shuts hypocrites out of Christ’s kingdom. On the left hand, he shuts out the Jews, and all such as will work their own salvation, saying, “In Christ neither circumcision,” that is to say, no works, no service, no worshipping, no kind of life in the world, but faith, without any trust in works or merits, avails before God. On the right hand he shuts out all slothful and idle persons, which say, if faith justify without works, then let us work nothing, but let us only believe and do what we list. Not so, you enemies of grace; Paul says otherwise. And although it is true, that faith alone justifies, yet he speaks here of faith in another respect; that is to say, that, after it hath justified, it is not idle, but occupied and exercised in working through love. Paul, therefore, in this place, sets forth the whole life of a Christian man, namely, that inwardly it consists in faith towards God, and outwardly in charity and good works toward our neighbor. So that a man is a perfect Christian inwardly through faith before God, who has no need of our works; and outwardly before men, whom our faith profits nothing, but only our charity or our works. Therefore, when we have heard or understood of this form of Christian life, viz., that it is faith and charity, (as I have said,) it is not yet declared what faith or what charity is; for this is another question. For as touching faith, or the inward nature, force, and use of faith, he hath spoken before, where he showed that it is our righteousness, or rather our justification before God. Here he joins it with charity and works, that is to say, he speaks of the external office thereof, which is to stir us up to do good works, and to bring forth in us the fruits of charity, to the profit of our neighbor.
Note that John Calvin, in his Commentary on Galatians, also makes the same careful distinction between the role of faith in justification and the role of faith working through love in sanctification:
With respect to the present passage, Paul enters into no dispute whether love cooperates with faith in justification; but, in order to avoid the appearance of representing Christians as idle and as resembling blocks of wood, he points out what are the true exercises of believers. When you are engaged in discussing the question of justification, beware of allowing any mention to be made of love or of works, but resolutely adhere to the exclusive particle. Paul does not here treat of justification, or assign any part of the praise of it to love. Had he done so, the same argument would prove that circumcision and ceremonies, at a former period, had some share in justifying a sinner. As in Christ Jesus he commends faith accompanied by love, so before the coming of Christ ceremonies were required. But this has nothing to do with obtaining righteousness, as the Papists themselves allow; and neither must it be supposed that love possesses any such influence.
The Westminster Divines (who do not hesitate to say that the grace of love is present in the heart of the believer when he first believes) explicitly note that it is not any other grace working with faith that justifies guilty sinners; it is by the instrumentality of faith alone:
Question 73: How does faith justify a sinner in the sight of God?
Answer: Faith justifies a sinner in the sight of God, not because of those other graces which do always accompany it, or of good works that are the fruits of it, nor as if the grace of faith, or any act thereof, were imputed to him for his justification; but only as it is an instrument by which he receives and applies Christ and his righteousness.
Nicholas T. Batzig is the organizing pastor/church planter of New Covenant Presbyterian Church, a PCA church in Richmond Hill, Georgia.