Therefore, as through one man’s offense judgment came to all men, resulting in condemnation, even so through one Man’s righteous act the free gift came to all men, resulting in justification of life. For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous. Moreover the law entered that the offense might abound. But where sin abounded, grace abounded much more, so that as sin reigned in death, even so grace might reign through righteousness to eternal life through Jesus Christ our Lord. (Romans 5:18-20; NKJV)
Even sin and it's ugly effects are not outside of God's control, and sin and its ugly effects display God's grace and redemption as glorious. Luther expressed it well when he wrote to Melanchthon that only a sinner can experience God's grace:
"If you are a preacher of Grace, then preach a true, not a fictitious grace; if grace is true, you must bear a true and not a fictitious sin. God does not save people who are only fictitious sinners. Be a sinner and sin boldly, but believe and rejoice in Christ even more boldly. For he is victorious over sin, death, and the world. As long as we are here we have to sin. This life in not the dwelling place of righteousness but, as Peter says, we look for a new heavens and a new earth in which righteousness dwells." (Weimar ed. vol. 2, p. 371; Letters I, "Luther's Works," American Ed., Vol 48. p. 281- 282)
Because of our unique position as sinful created beings whom God has redeemed for Himself, we have the opportunity to experience His grace in a way that would never be possible in a world without sin. So, sin in the body of Christ is an opportunity to forgiven each other because Christ has forgiven us and to display His redemption and grace against the backdrop of human sin. With Luther, while we fight sin dwelling in our flesh, we "look for new heavens and a new earth in which righteousness dwells" (2 Peter 3:13; NKJV).
