Saved people do not live after the flesh. They did that before they were saved (Rom 6:1-2, 6-22; 8:1-9; Eph 2:1-3). The “old man IS crucified with [Christ]” (Rom 6:6; Gal 2:20; 5:24). Saved people “have put off the old man with his deeds; And have put on the new man, which is renewed in knowledge after the image of him that created him” (Col 3:9-10). Sound exegesis makes it obvious that Gal 5:19-21; 1 Cor 6:9-10; and 15:50 are referring to the same thing: those that live after the flesh will not and “cannot inherit the kingdom of God,” which means to not inherit heaven. It means they are unregenerate and lost.
Claiming these passages as referring to the flesh of a saved person not inheriting the kingdom of God, is twisting a very plain passage and teaching of scripture, and confusing Gods Word. When the Bible speaks of those who live after the flesh and will not inherit the kingdom of God (Gal 5:19-21; 1 Cor 6:9-10; Eph 5:5-8), it is ONLY referring to lost people. Even the very context of Gal 5:19-21 tells us this. “And they that are Christ's HAVE crucified the flesh with the affections and lusts.” (Gal 5:24). “Have” like “is” is aorist, Greek perfect tense verbs that indicate a perfected state in the present tense based upon a past event (salvation) which keeps continuing into the future.
Those that live after the flesh as seen in Gal. 5:19-21; 1 Cor 6:9-10 and Eph 5:5-8 are “dead IN sins” (Rom 6:2,7,11; Eph 2:5; Col 2:13) and under the law for sin has yet dominion over them (Rom 6:14-15) and are “the servants of sin” (Rom 6:17-18, 20) and “free from righteousness” (Rom 6:20), thus are under the punishment of death “for the wages of sin is death” (Rom 6:23) while the truly saved are “dead TO sins” (1 Pet 2:24) and have “eternal life” (Rom 6:23) and thus will never die (Jn 6:50-51; 11:25-26). “But now being made free from sin, and become servants to God, ye have your fruit unto holiness, and the end everlasting life.” (Rom 6:22).
Consider a brief exposition of these passages.
Galatians 5:18-21
This passage not speaking of the flesh of a Christian that doesn’t inherit the kingdom of God. Paul is warning the Galatians (and its not the first time either, according to v 21) that if any man lives after the flesh, he is lost and will never inherit heaven. He is still under the law (v 18), which means he is still lost (Rom 3:19; Gal 3:1-3; 5:18). Its the exact same warning Paul wrote to the Corinthians (1 Cor 6:9-10) and Ephesians (Eph 5:5-8). Paul is contrasting true believers in the church at Galatia (“ye” v 18) with the unsaved in the church of Galatia (“they,” v. 21)—which contrast applies to all peoples of all ages. The contrast is continual throughout this chapter and the Bible.
When the Bible affirms that “they which do such things [those who practice such sins, vv. 19-21] shall not inherit the kingdom of God” (v. 21), it is impossible to interpret this warning as merely a loss of reward or referring to the flesh of a saved person, for those who actually end up in heaven anyway. None of the 18 references to the verb "inherit" in the NT distinguish between a higher class of believers that inherit the kingdom and a lower class that somehow are saved but do not have an inheritance, or a believer who inherits heaven but his flesh doesn’t (Matt 5:5; 19:29; 25:34; Mk 10:17; Lk 10:25; 18:18; 1 Cor 6:9-10; 15:50; Gal 4:30; 5:21; Heb 1:14; 6:12; 12:17; 1 Pet 3:9; Rev 21:7); rather, the contrast is between those truly saved, and thus “inherit everlasting life” (Matt 19:29), “inherit the kingdom” (Matt 25:34), “inherit the [Millennial] earth” (Matt 5:5), “inherit eternal life” (Mk 10:17), “inherit the kingdom of God” (1 Cor 6:9-10; Gal 5:21), and “inherit all things” (Rev 21:7), and the lost who do not inherit eternal life and the kingdom of heaven. Gal 5:19-21, like 1 Cor 6:9-10 is referring to a people, NOT the flesh of a saved person, who do not inherit Gods kingdom.
1 Corinthians 6:9-11
This passage similarly teaches that true believers will not live as fornicators, idolators, adulterers, sodomites, thieves, and so on, because they have a new nature, “And such were some of you: but ye are washed ... sanctified and ... justified in the name of the Lord Jesus, and by the Spirit of our God” (v. 11). Those who receive condemnation are not “carnal Christians,” but the unregenerate. The “unrighteous” of vv. 9-10, who will be excluded from God’s kingdom, are the “unjust” of 1 Cor 6:1, the one who is not a brother but an unbeliever (1 Cor 6:6). Indeed, Scripture regularly contrasts the believer and the unbeliever as “the just and the unjust” (Ac 24:15; Matt 5:45; 2 Pet 2:9), but the regenerate are never called “unrighteous” anywhere in the Bible (Matt 5:45; Lk 16:10–11; 18:11; Ac 24:15; Rom 3:5; 1 Cor 6:1, 9; Heb 6:10; 1 Pet 3:18; 2 Pet 2:9). All believers are, in contrast, not the “unrighteous” but those righteous before God (v 11) because of their justification and sanctification. “If ye know that he is righteous, ye know that every one that doeth righteousness is born of him.” (1 Jn 2:29).
Position and practice is NOT divorced. Practice ALWAYS follows the position. A contrast is not being made between disobedient and obedient believers or the flesh and the spirit of a believer in vv. 9-11, but between the people of God and the children of the devil.
Ephesians 5:5-8
Similarly, the related noun inheritance is regularly used to contrast what all saved people receive and all unsaved people do not. Ephesians indicates that all who have the indwelling Spirit have the inheritance (Eph 1:13-14), all the predestinated have the inheritance (Eph 1:11, 18), but “no whoremonger, nor unclean person, nor covetous [envious] man, who is an idolater, hath any inheritance in the kingdom of Christ and of God” (Eph 5:5), for all such are “the children of disobedience” under the “wrath of God” (Eph 5:6; 2:1-3) who have not been brought into union with Christ by repentant faith and inwardly changed (Eph 2:4-10) and made into “children of light” (Eph 5:8).
All those who have been “begotten ... again” have an “inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven” (1 Pet 1:3-4). While the noun inheritance is sometimes used for the physical passing on of property to heirs by those who have deceased (e.g. Lk 12:13), the noun, like the verb to which it is related, never contrasts a higher class of saved people from a lower class of those who are saved but have no inheritance or lose their rewards or the flesh not inheriting the kingdom of God (Matt 21:38; Mk 12:7; Lk 12:13; 20:14; Ac 7:5; 20:32; Gal 3:18; Eph 1:14, 18; 5:5; Col 3:24; Heb 9:15; 11:8; 1 Pet 1:4).
1 Corinthians 15:50
This passage is also a casualty of this error. This passage (“Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption”) is telling us that a person in his “natural body” (vv. 44-49) that of mere “flesh and blood” which is corruption, will not inherit the kingdom of God and incorruption. What Jn 1:13 is tell us, those genuinely converted “were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.” The contrast is being made between the saved and lost, like the other passages.
Just because he’s writing this to the “brethren” doesn’t mean it applies to the brethren; we also know that they weren’t all saved at Corinth (there was unsaved people at Corinth who considering themselves to be Christians and brethren: 1 Cor 5; 2 Cor 12:20–13:5). Flesh and blood is natural, but the new birth is spiritual. The first Adam brought death (natural man) while the second Adam brought life (the spiritual man) (1 Cor 2:9-16; 15:44-50; Rom 5). Every person that is lost is only a “natural man” (1 Cor 2:14) and has only a “natural body” (vv 44-46). When a person gets saved, he is a spiritual man (1 Cor 2:9-16) with the promise of future glorification with a spiritual body (Rom 8:29).
Concluding, to claim that Gal 5:19-21 is teaching the flesh of a saved person not inheriting Gods kingdom is confusion and contrary to that passage, and to similar passages such as 1 Cor 6:9-10; 15:50 and Eph 5:5-8, and does not harmonize with the remainder of scripture. These passages are contrasting saved and lost people, nothing do with some variance within a person. Rom 7:14-25 is not teaching that saved people live characteristically after the flesh or in sin. It’s simply teaching us the struggle that can exist in the true believer, while at the same time telling us that the victory is already won in Christ Jesus (v. 25). 1 Cor 2:14, the “natural man,” is very clearly a lost person.
Misusing these passages will tolerate disobedience and prevent false pretenders from being truly converted. Instead of maintaining a narrative, we must carefully study and exegete the Word, looking at it grammatically and contextually and rightly divide the word. God's Word is plain and perspicuous (Pr 8:8-9; 22:20-21), and its every word is important since we are to live by every word (Matt 4:4). If the meaning of Scripture is mangled and incongruous, is the Holy Spirit in it? God doesn’t work in a way that circumvents the Bible.