Summary: The apostles, especially Paul, said much about the walk in the Spirit. We would do well not to ignore what was said.
IN THE WRITINGS OF PAUL
11 For I long to see you, that I may impart to you some spiritual gift, so that you may be established-- 12 that is, that I may be encouraged together with you by the mutual faith both of you and me.
Paul wanted to be with the Roman believers. His heart was to establish them in the things of God. Now, he was a man of the Scriptures, and would surely share the Word and the Gospel with them. They easily had access to the Old Covenant already, and whatever teachings were needed for them Paul and other teachers could supply.
But what Paul wanted to impart was a spiritual gift, that is, a gift of the Spirit. He wanted to lay hands on them and give them the supernatural ability to know and to experience heavenly realities. Later he mentions he wanted to see fruit among them too, and he writes them this extensive letter that goes deep into doctrine. But let us not fail to see that doctrine and scripture, wonderful in themselves, are meant to point people to an encounter with Jesus. One without the other is not a complete empowering.
Here is a chapter that has been embraced by so much of the church, from those seeking personal direction for the Spirit-filled walk to those who love a good debate. My purposes again are to speak what the apostles spoke about the Spirit in the church, for our day.
1 There is therefore now no condemnation to those who are in Christ Jesus, who do not walk according to the flesh, but according to the Spirit. 2 For the law of the Spirit of life in Christ Jesus has made me free from the law of sin and death. 3 For what the law could not do in that it was weak through the flesh, God did by sending His own Son in the likeness of sinful flesh, on account of sin: He condemned sin in the flesh, 4 that the righteous requirement of the law might be fulfilled in us who do not walk according to the flesh but according to the Spirit. 5 For those who live according to the flesh set their minds on the things of the flesh, but those who live according to the Spirit, the things of the Spirit. 6 For to be carnally minded is death, but to be spiritually minded is life and peace. 7 Because the carnal mind is enmity against God; for it is not subject to the law of God, nor indeed can be. 8 So then, those who are in the flesh cannot please God. 9 But you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. Now if anyone does not have the Spirit of Christ, he is not His. 10 And if Christ is in you, the body is dead because of sin, but the Spirit is life because of righteousness. 11 But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ from the dead will also give life to your mortal bodies through His Spirit who dwells in you.
It is possible to walk and live according to the Spirit. None would debate that, for sure, but what exactly does it mean to be “in the Spirit,” the phrase of verse 9? Whatever it means, Paul rules out ever pleasing God if you are not there.