16 I say then: Walk in the Spirit, and you shall not fulfill the lust of the flesh. 17 For the flesh lusts against the Spirit, and the Spirit against the flesh; and these are contrary to one another, so that you do not do the things that you wish. 18 But if you are led by the Spirit, you are not under the law (Galatians 5:16–18, NKJV).
In today’s passage, walking in the Spirit is equivalent to being led by the Spirit (v. 16, 18). Being led by the Spirit is a matter of free will, a choice to live by faith. The Spirit does not force Himself upon anyone. Being led by the Spirit is tantamount to living in the Spirit. By crucifying the flesh with its passions and bearing the fruit of the Spirit (Gal. 5:22-25). Again, this is a choice of faith we make, a life we choose to live. The Spirit of God leads Christians when we hear (and obey) the gospel (the faith, Gal. 3:1-2; 1:11, 23). The Holy Spirit revealed the gospel, confirmed its validity through miracles, and inspired its proclamation (Heb. 2:1-4; Eph. 3:3-5). When we follow the Scriptures, we are following the Spirit of God. Do not expect the Spirit to act upon you in some way distinct from His word. He is speaking through His word to you and me. We walk in the Spirit when we submit to the gospel of Christ (Rom. 8:1-2, 5-8). See this choice of faith to follow the word of God and live by the Spirit in Romans 8:13, “For if you live according to the flesh you will die; but if by the Spirit you put to death the deeds of the body, you will live.” We are alive in Christ and are led by the Spirit when we choose to live according to the gospel He revealed.