We combat our fleshly nature with God's grace. When we accept that we are forgiven by Christ Jesus, we are better able to forgive others. If we cannot forgive, we give the enemy a foothold. And if you give him an inch, he will take a mile. If you get angry for a moment, (temporarily), that's okay, accept it, but don't let it take root. Don't deny that it's there; face it.... and accept that because you are human (flesh) you will find yourself at times doing things that are not in sync with the nature of our Father in Heaven. Nowhere in His word does it say that we will never succumb to temptation, nor that we will live holy, untainted, sinless lives; never getting upset, experiencing feelings of bitterness, jealousy, impatience, anger, etc. So long as satan roams the earth, we (our flesh) will be susceptible to these things. There is no sense is denying this and saying that we won't ever experience them. But we are new creations in Christ. This means; the work that the Holy Spirit is doing in us, will continually strengthen us to be able to combat the nature of our flesh. So that although we may succumb to it temporarily, we do not have to be trapped by it permanently.
What do we believe as Christians? That Christ died for our sins. That by the admission and repentance of sins, we are forgiven, and our sin is covered by His grace.
If this is truly our belief, if we firmly accept this statement above as the Truth, we must choose to forgive others in the same manner in which Jesus forgave us, and that includes forgiving ourselves. God's grace (His ability to forgive us) is what allows us to forgive others; and the Faith we have that God has indeed forgiven us allows us to forgive ourselves. These are our greatest weapons against succumbing to our inherent nature. There is big difference between sinning and becoming sin. It is when we choose to stay in the bondage of sin, (lingering in condemnation), rather than accepting our Father's forgiveness, that we begin to lose our footing in the stand against the enemy. What God is saying to us in His word is: He understands that we will sin, it is why He sent Christ, but He does not want us to stay in sin, it is why Christ died for Grace to be extended to us. He understands we may fall but He expects us to allow His gift of grace to pick us back up. We can't make ourselves righteous but by accepting that He can, we no longer interfere with The Holy Spirit's work in us. When we stop trying to stop sinning by our own strength, we allow God's strength to step in; we allow His truth, to transform us from our inherent nature to our intended one.
“Go ahead and be angry. You do well to be angry—but don’t use your anger as fuel for revenge. And don’t stay angry. Don’t go to bed angry. Don’t give the Devil that kind of foothold in your life.”
- Ephesians 4:26-27 MSG
“Watch what God does, and then you do it, like children who learn proper behavior from their parents. Mostly what God does is love you. Keep company with him and learn a life of love. Observe how Christ loved us. His love was not cautious but extravagant. He didn’t love in order to get something from us but to give everything of himself to us. Love like that.”
- Ephesians 5:1-2 MSG