How do we know grace is sufficient against sin?

Grace is described in Romans as a sovereign force that reigns through righteousness, providing strength against sin. Romans 5 elaborates that while sin reigned unto death, grace abounds through Jesus Christ, offering eternal life. This means that our strength against sin does not lie in our effort but in Christ's accomplished work and His righteousness bestowed upon us. As believers, we are united with Christ in His death and resurrection, which allows us to serve God in the newness of spirit instead of the oldness of the letter of the law. As such, while we continue to struggle with sin in our lives, we do not live under the law's dominion but under the grace that empowers us to overcome sin through faith in Christ.