“The Flesh” in Romans
The unbeliever, of course, since He does not have the Spirit of God, has no choice but to operate through the flesh. As we have seen in the discussion about
the three parts of a person, this says nothing whatsoever about the ability (or inability) of the unregenerate person to believe in Jesus for eternal life. It is not “the flesh” that believes in Jesus, but the spirit.
Proverbs 20:27 The spirit of man is the candle of the Lord, searching all the inward parts of the belly.
So while Paul is absolutely right that the flesh cannot please God, we should not understand Paul to be saying that a person cannot believe in Jesus for eternal life. God calls all to believe in Jesus, and since faith is not a work of the spirit through the corrupted flesh, our spirit convicted by the Holy Spirit is able to believe in Jesus and receive eternal life from Him. The transition from death into life occurs when we believe the Gospel message..
John 5:24 “Very truly I tell you, whoever hears my word and believes him who sent me has eternal life and will not be judged but has crossed over from death to life.
Ephesians 1:13 And you also were included in Christ when you heard the message of truth, the gospel of your salvation. When you believed, you were marked in him with a seal, the promised Holy Spirit,
1 Timothy 4:10 That is why we labor and strive, because we have put our hope in the living God, who is the Savior of all people, and especially of those who believe.
Unbelievers are Not the Focus on Romans 8:7-8
Of course, having said this, it is important to note that the unregenerate person is not the subject of Paul’s statement in Romans 8:7-8.
Instead, Paul is writing about
the experience of believers.
In Romans 7, he wrote about the ongoing struggle with sin that every person experiences (both believer and unbeliever alike), and concluded that description by rejoicing that God has provided a way through Jesus Christ for people to be freed from the bondage to decay and corruption that was brought about by the body of death. As a result of Jesus and the indwelling Holy Spirit, our mind can side with our regenerated spirit now serve the law of God, even though the flesh still serves the law of sin (Romans 7:25).
Taken with some edits from
Romans 8:7-8, Enmity with God, and Calvinism