This phrase and its meaning comes from Galatians 5:16-25:
16 “But I say, walk by the Spirit, and you will not carry out the desire of the flesh. 17 For the flesh sets its desire against the Spirit, and the Spirit against the flesh; for these are in opposition to one another, so that you may not do the things that you please. 18 But if you are led by the Spirit, you are not under the Law. 19 Now the deeds of the flesh are evident, which are: immorality, impurity, sensuality, 20 idolatry, sorcery, enmities, strife, jealousy, outbursts of anger, disputes, dissensions, factions, 21 envying, drunkenness, carousing, and things like these, of which I forewarn you, just as I have forewarned you, that those who practice such things will not inherit the kingdom of God. 22 But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, 23 gentleness, self-control; against such things there is no law. 24 Now those who belong to Christ Jesus have crucified the flesh with its passions and desires. 25 If we live by the Spirit, let us also walk by the Spirit.”
The Christians in Galatia were struggling with worldly influences coming in among them from several sources. First, there were Christians who came from a Jewish background and believed that all Christians were bound to follow the Jewish Law. Then there were the Christians who came from blatantly Pagan backgrounds. They had to be taught how to live up to Christian standards while flatly rejecting their old ways of life. Christian discipleship has no room for any of this.
In chapter 5 verse 16 of his letter to the Galatians, Paul takes a deep dive into these issues. He begins with a simple statement, “Walk by the spirit, and you will not carry out the desire of the flesh.” He then goes on to list the “deeds of the flesh.” This was no simple list, as it consisted of 15 different internal and external behaviors for Christians to avoid. Looking closely at this list, we see it is broken down into five basic categories of fleshly deeds.
We might expect that such a comprehensive list of the deeds of the flesh would begin with making sure God is always first. Though idolatry seems to be the most widely pointed out sin in the Bible, it is not at the top of Paul’s list. He chose instead to begin with sins of human desire. His first three fleshly deeds to avoid were immorality, impurity and sensuality. When we step back and look at how human nature works, we can really begin to grasp why Paul begins with these difficult aspects of life.
Paul followed up this list of what not to do with the beautiful list of the fruit of the Spirit.