The apostle Paul says that since Adam’s fall, human beings have inherited a fallen sinful nature (Romans 5:19). This inner nature always acts in rebellion against God and His law. Paul says that even when a person has become a Christian, this sinful nature still clings on and wrestles against us. The sinful nature is opposing the Spirit of God, trying to reclaim its throne in our hearts (Romans 7:1-25). Someone who has come to faith in Christ has to learn to put this sinful nature (or flesh) to death and instead listen to the Holy Spirit (Galatians 5:13-25, translated here as ‘flesh’ - a more literal translation of the Greek word sarx). When Christians receive their new bodies at the resurrection of the dead, their sinful nature will no longer have a part of them and they will be perfect (Romans 8:23). (See Depravity, Flesh)
Sinful Nature
See also
Depravity
Flesh