So that, [just] as sin has reigned in death, [so] grace (His unearned and undeserved favor) might reign also through righteousness (right standing with God) which issues in eternal life through Jesus Christ (the Messiah, the Anointed One) our Lord. – Romans 5:21 (AMP)
Grace reigns through righteousness. Grace reigns when we focus on being the righteousness of God in Christ Jesus. It reigns when we focus on Jesus and what He has done for us instead of focusing on our own efforts, which Isaiah 64:6 calls filthy rags. Rely on Jesus and Jesus alone, and see grace reign supreme in your life.