If we live in the Spirit. According to his usual custom, the apostle draws from the doctrine a practical exhortation. The death of the flesh is the life of the Spirit. If the Spirit of God lives in us, let him govern our actions. There will always be many persons daring enough to make a false boast of living in the Spirit, but the apostle challenges them to a proof of the fact. As the soul does not remain idle in the body, but gives motion and rigour to every member and part, so the Spirit of God cannot dwell in us without manifesting himself by the outward effects. By the life is here meant the inward power, and by the walk the outward actions. The metaphorical use of the word walk, which frequently occurs, describes works as evidences of the spiritual life.

If we live in the Spirit - See the note at Galatians 5:16. The sense of this verse probably is, "We who are Christians profess to be under the influences of the Holy Spirit. By his influences and agency is our spiritual life. We profess not to be under the dominion of the flesh; not to be controlled by its appetites and desires. Let us then act in this manner, and as if we believed this. Let us yield ourselves to his influences, and show that we are controlled by that Spirit." It is an earnest exhortation to Christians to yield wholly to the agency of the Holy Spirit on their hearts, and to submit to his guidance; see Romans 8:5, note9, note.

If we live in the Spirit - If we profess to believe a spiritual religion, let us walk in the Spirit - let us show in our lives and conversation that the Spirit of God dwells in us.

If we (l) live in the Spirit, let us also walk in the Spirit.
(l) If we are indeed endued with the quickening Spirit, who causes us to die to sin, and live to God, let us show it in our deeds, that is, by holiness of life.

If we live in the Spirit,.... Or "by the Spirit", as all do that are spiritually alive. Sin has not only brought on men a corporeal death, and made them liable to an eternal one, but has also induced upon them a spiritual or moral death; they are dead in trespasses and sin, nor can they quicken themselves, nor can any creature give them life; not the ministers of the word, nor the angels in heaven, only the blessed Spirit is the spirit of life from Christ; who entering into them, frees them from the law of sin and death, and implants a principle of spiritual life in them, whereby they live a life of faith on Christ, of holiness from him, and communion with him: and this the apostle makes use of, as an argument with believers to walk after the Spirit,
let us also walk in the Spirit: or "by the Spirit"; by his help and assistance, according to the rule of his word, and under his influence and direction as a guide, to which he had before advised in Galatians 5:18.

in . . . in--rather, as Greek, "If we live (see on Galatians 5:24) BY the Spirit, let us also walk (Galatians 5:16; Galatians 6:16) BY the Spirit." Let our life in practice correspond to the ideal inner principle of our spiritual life, namely, our standing by faith as dead to, and severed from, sin, and the condemnation of the law. "Life by (or 'in') the Spirit" is not an occasional influence of the Spirit, but an abiding state, wherein we are continually alive, though sometimes sleeping and inactive.

If we live by the Spirit - If we are indeed raised from the dead, and are alive to God, by the operation of his Spirit. Let us walk by the Spirit - Let us follow his guidance, in all our tempers, thoughts, words, and actions.