What does the Bible say about the conflict between the flesh and the spirit?

Scripture clearly illustrates the battle between the flesh and the spirit in the life of a believer. The Apostle Paul in Romans 7 expresses this conflict profoundly, stating, 'O wretched man that I am! Who shall deliver me from the body of this death?' This reveals the ongoing war within every Christian, where the desire to do good contrasts with the reality of sin still present. Additionally, Galatians 5:17 states, 'For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other.' This indicates that believers are engaged in a spiritual warfare that is not only internal but reflective of a greater theological truth: that salvation does not erase the old nature but coexists with the new creation in Christ.