Sin is not to have the final word in the human heart; holy-making grace is to have the final word.  The place where sin abounded is the place where grace now abounds more (Romans 5:20).  The essence of sin is the failure to love.  The love of God is poured into our hearts by His Spirit (Rom 5:5).  Never emphasize the power of sin in the human heart unless you quickly emphasize the power of grace to overcome sin and make us holy.

“Where sin increased, grace abounded all the more, so that, as sin reigned in death, even so grace would reign through righteousness to eternal life through Jesus Christ our Lord” Romans 5:20-21 (NASB).