Let not sin therefor reign in your mortal body, that ye should obey it in the lust thereof. Romans 6:12
Once sin reigned over the believing sinner like a tyrant reigns over a city. His laws and design are to enslave and hurt the people under his tyrannical reign. But when a better king comes and tares down the tyrant from his occupied throne and sets himself up as ruler over the people, he brings in justice and mercy. The once ruling tyrant is no longer master and is now an outlaw. He may remain in that city but only as an annoyance seeking to trouble the people with lesser power. So it may be with the Christian who was once governed by sin as master but when Christ came, He defeated sin and set up His rule and reign in the heart and life of the believer. Sin may remain, but not as master. Just as the new and better king will use his power to drive out the old tyrant and all his remaining effects, so Christ in sanctification drives out sin and its remaining effects in the life of the believer. Thus we must give no place to that old tyrant of sin in our mortal bodies. His rule and power has been broken by Christ triumph on the cross. The war is won but battles remain. The fight against the enemies is one of guaranteed victory. Just as God told Joshua “I have given the enemy into your hand” (Joshua 10:19) but commanded Joshua to pursue and destroy the inhabitants of Canaan , so we, having Christ as our victor who has already won the victory, still commands us to fight sin with encouraging words like “Sin shall not have dominion over you.”(Romans 6:14), and “In the world ye shall have tribulation: but be of good cheer; I have overcome the world.” (John 16:33). We must continually look to Christ for all comforts and strength is the remaining battle against sin. His promise to never cast you away (John 6:37), and to “Never leave you nor forsake you” (Hebrews 13:5) based on his covenant promise should be your strength in the easy times, as well has the tough times of the battle. David says “I have hid your word in my heart that I might not sin against you” (Psalms 119:11). We should make the word of God our constant diet in all times, not just desperate ones. We must know the word in order to be able to use it in every season. Above all, be encouraged and rejoice always because in Christ all grace is afforded to you! God is for you, even in your sin. He is either calling you out of it(Repentance), or sustaining you in the battle (perseverance), either way, know Christ is your final hope and salvation. He has accomplished all that was and is necessary for your salvation. Trust in your new King! He has you covered!