But if ye be led of the Spirit - If you submit to the teachings and guidance of the Holy Spirit.

Ye are not under the law - You are under a different dispensation - the dispensation of the Spirit. You are free from the restraints and control of the Mosaic law, and are under the control of the Spirit of God.

But, if ye be led of the Spirit - If ye receive again the Gospel and the grace of Christ, and permit yourselves to be influenced by the Holy Spirit whom you are now grieving, ye are not under the law - ye will not feel those evil propensities which now disgrace and torment you; but they must prevail while you are not under the influence of the grace and Spirit of Christ.

But if ye be led by the Spirit,.... That is, of God, who is the guide and leader of his people. It is a metaphor taken from the leading of persons that are blind; as such are before conversion, and whom the Spirit of God leads in ways they knew not, and in paths they had not known: or from the leading of children, and teaching them to go; so the Spirit leads regenerate persons, and teaches them to walk by faith in Christ. This act of leading supposes life in the persons led, for dead men cannot be led; the Spirit is first a Spirit of life from Christ before he is a leader; and also it supposes some strength, though a good deal of weakness; were there no spiritual strength derived from Christ, they could not be led; and if there was no weakness, there would be no need of leading; it is an instance of powerful and efficacious grace upon them, yet not contrary to their wills, though they are led, they are not forced; they go freely, being led, as there is good reason for it; for the Spirit of God always leads for their profit and advantage, and for the spiritual delight, pleasure, and comfort of their souls; he leads out of the ways of sin, and so of ruin and destruction, and from Mount Sinai, and all dependence on a legal and moral righteousness; he leads to Christ, to his person, for shelter, safety, and salvation, to his blood, for pardon and cleansing, to his righteousness, for justification, and to his fulness, for every supply of grace; he leads into the presence of God, and to his house and ordinances; he leads into the covenant of grace, to the blessings, promises, and Mediator of it; he leads into all truth as it is in Jesus, in the ways of faith and truth, and in the paths of righteousness and holiness, and always in a right way, though sometimes in a rough one, to the city of their habitation; he leads from one degree of grace to another, and at last to glory: all which he does gradually; he leads by little and little into a man's sinfulness, and to see his interest in Christ, and by degrees into the doctrines of the Gospel, and the everlasting love of the three Persons; and proportionally to the strength he gives, and as they are able to bear: now such persons as these have nothing to fear from the law of God:

ye are not under the law; such are not only delivered from the law in fact, but in their own apprehensions; they have the comfortable knowledge and experience of it; the law is no terrifying law to them; it works no wrath in them; they are delivered from the spirit of bondage to fear, by the Spirit of God, by whom they are led; nor are they under it, nor do they need it as a pressing forcing law to duty; they delight in it, and cheerfully serve it, being constrained by love, and not awed by fear; nor are its accusations and charges regarded, or to be regarded, by such who are led by the Spirit to Christ, the end of the law for righteousness; and they are entirely freed from its curse and condemnation, though they are under it, and desire to be under it, as held forth by Christ the King of saints; and, under the Spirit's influence and guidance, yield a cheerful and evangelical obedience to it.

The question is, which of these two powers shall prevail. If the Spirit, then you are free men, no longer under the law. Comp. Romans 6:11, Romans 6:14.

Under the law (ὑπὸ νόμον)

The Mosaic law. We might have expected, from what precedes, under the flesh. But the law and the flesh are in the same category. Circumcision was a requirement of the law, and was a work of the flesh. The ordinances of the law were ordinances of the flesh (Hebrews 9:10, Hebrews 9:13); the law was weak through the flesh (Romans 8:3). See especially, Galatians 3:2-6. In Philippians 3:3 ff. Paul explains his grounds for confidence in the flesh as his legal righteousness. The whole legal economy was an economy of the flesh as distinguished from the Spirit.

But if ye be led of the Spirit, ye are not under the law.

5:18 But if ye be led by the Spirit, ye are not under the law. If the desire of the Spirit prevails. Those led of the Spirit are the sons of God (Ro 8:14), and are free from the law. The law with its carnal ordinances in Paul's view was adapted to a fleshly condition.

5:18 But if ye are led by the Spirit - Of liberty and love, into all holiness. Ye are not under the law - Not under the curse or bondage of it; not under the guilt or the power of sin.

Margin under the law

i.e. not under bondage of effort to please God by law-works. 2Cor 3:17.

18. "If ye are led (give yourselves up to be led) by (Greek) the Spirit, ye are not under the law." For ye are not working the works of the flesh (Ga 5:16, 19-21) which bring one "under the law" (Ro 8:2, 14). The "Spirit makes free from the law of sin and death" (Ga 5:23). The law is made for a fleshly man, and for the works of the flesh (1Ti 1:9), "not for a righteous man" (Ro 6:14, 15).

5:16-26 If it be our care to act under the guidance and power of the blessed Spirit, though we may not be freed from the stirrings and oppositions of the corrupt nature which remains in us, it shall not have dominion over us. Believers are engaged in a conflict, in which they earnestly desire that grace may obtain full and speedy victory. And those who desire thus to give themselves up to be led by the Holy Spirit, are not under the law as a covenant of works, nor exposed to its awful curse. Their hatred of sin, and desires after holiness, show that they have a part in the salvation of the gospel. The works of the flesh are many and manifest. And these sins will shut men out of heaven. Yet what numbers, calling themselves Christians, live in these, and say they hope for heaven! The fruits of the Spirit, or of the renewed nature, which we are to do, are named. And as the apostle had chiefly named works of the flesh, not only hurtful to men themselves, but tending to make them so to one another, so here he chiefly notices the fruits of the Spirit, which tend to make Christians agreeable one to another, as well as to make them happy. The fruits of the Spirit plainly show, that such are led by the Spirit. By describing the works of the flesh and fruits of the Spirit, we are told what to avoid and oppose, and what we are to cherish and cultivate; and this is the sincere care and endeavour of all real Christians. Sin does not now reign in their mortal bodies, so that they obey it, Ro 6:12, for they seek to destroy it. Christ never will own those who yield themselves up to be the servants of sin. And it is not enough that we cease to do evil, but we must learn to do well. Our conversation will always be answerable to the principle which guides and governs us, Ro 8:5. We must set ourselves in earnest to mortify the deeds of the body, and to walk in newness of life. Not being desirous of vain-glory, or unduly wishing for the esteem and applause of men, not provoking or envying one another, but seeking to bring forth more abundantly those good fruits, which are, through Jesus Christ, to the praise and glory of God.