Walking in the Spirit is a matter of choice, but it is more complicated than simply a matter of choice. To begin with, the flesh is at war with the Spirit (Galatians 5:17). In other words, the flesh or the natural man (1Corinthians 2:14) will not embrace the things of the Spirit, because spiritual matters are foolishness to the natural order of things—or how the natural man (viz. the spirit of man) understands his world. The natural man compares physical evidence with physical evidence in order to draw his conclusions, but the spiritual man compares spiritual matters with spiritual matters (1Corinthians 2:13). The natural man has no frame of reference in spiritual matters, because they are spiritually discerned, i.e. they are understood through the Spirit of God which is given to believers (cf. 1Corinthians 2:14 and Galatians 5:17).
Paul is not describing two warring natures in Galatians 5:17. He describes two warring natures in Romans 17:13-24. In Galatians 5 the opponents are the flesh and the Spirit of God, while in Romans 7 the opponents are the flesh and the regenerated or born-again believer. In Galatians 5 we are given a choice which could result in victory or failure, but in Romans 7 we are given an example of making the wrong choice, that is, believing now that we are reborn we have power to overcome the flesh. We don’t. In Romans 7:24 Paul wonders who could save him from the inevitable defeat of his born-again self by the more powerful natural man, which he calls the “body of flesh”. He answers his own query in Romans 7:25a by saying: “Thanks be to God (it is) through Jesus Christ our Lord…” or in Paul’s words to the Galatians: “Walk in the Spirit (of Christ), and you will not fulfill the desires of the flesh (Galatians 5:16).
In Romans 6:6 Paul describes the flesh as the old man and the body of sin. The old man is trained in the things of the world in order to please or build up the world; he is also trained in the things of the flesh in order to please his own desires and both the world and the flesh are enemies of God (cf. Ephesians 2:2-3). According to Romans 7:8, the old man is weak when faced with the demands of the Law, and the Law seems to serve more as a temptation to do evil than to change his behavior. However, we who walk after the Spirit are not under the Law’s power or authority (Galatians 5:18), so the weakness of the old man has no bearing on those who are new creatures (Galatians 6:15; cf. 2Corinthians 5:17) and follow after the Spirit. How so? We walk in the Spirit by fixing our eyes upon Jesus (Hebrews 12:1-2), that is, turning our attention to him, and allow the Spirit to teach us by doing as Jesus would do (Matthew 11:28-30). By making ourselves alive to Christ (i.e. turn our attention to him), we are “reckoning” our old man (i.e. the flesh) to be dead (Romans 6:1-6, 11).
Paul’s use of the word if in Galatians 5:18 has great significance. If we are not led by the Spirit, we are under the Law. It is not a foregone conclusion that, because we are new creatures, we will be led by the Spirit. We must practice trusting in Christ in what we say and do, which is walking in the Spirit.
The works of the flesh (Galatians 5:19-21) are obvious (verse-19), and Paul names them, because it is difficult for those who have backslidden to understand that the fruit they bear is not the fruit of the Spirit. We, who have failed, need things spelled out for us, until we are walking in the Spirit once again and are able through the Spirit to discern correctly good from evil.
We could categorize the list Paul gives us in Galatians 5:19-21 into
- sensual sins: immorality, fornication, impurity, uncleanness (Gr. akatharsia, all moral uncleanness in thought, word, and deed), sensuality, licentiousness, indecency debauchery, lasciviousness (Gr. aselgeia, the open, shameless display of these sins);
- religious sins: idolatry” (Gr. eidololatria, worship of anything but God and the practices associated with that worship), sorcery, witchcraft (Gr. pharmakeia, attempts to aid the powers of evil and the practices associated with that);
- sins against personal relationships or people sins: enmities, quarrels, hatred (Gr. echthrai, hostilities), strife, discord, variance (Gr. eris, antagonism), jealousy, envy, emulation (Gr. zelos, self-centered animosity), outbursts of anger, fits of rage, wrath (Gr. thymoi, temper eruptions), disputes, strife, factions selfishness, selfish ambition (Gr. eritheiai, putting others down to get ahead), dissensions, divisions, seditions (Gr. dichostasiai, disputes over issues or personalities), factions, heresies, party spirit (Gr. haireseis, divisions over issues or personalities), envying, jealousies (Gr. phthonoi, wrong desires to have another’s possessions). The general impression created by these words is one of chaos.”
- social sins: drunkenness, drinking bouts (Gr. methai, excessive use of intoxicants), carousings, revelings, orgies (Gr. komoi, parties involving excessive eating and drinking)
Those who live like this will not inherit the Kingdom of God, that is, they will never receive the Spirit of God which governs God’s people (his Kingdom). Walking in the Spirit is characterized by loving one another, but walking in the flesh is characterized by putting self first—or before our brethren (1John 3:1-11). He who walks in the flesh will practice sinful behavior such as that described in Galatians 5:19-21, but he who walks after the Spirit will not behave like that (Galatians 5:16). We obey the Spirit by working out our lives with fear and trembling, trusting that God in us (the Spirit) will produce within us to desire to perform his will (Philippians 2:12-13).