Satan is known as the "accuser of the brethren" because he seeks to slander and discredit believers before God, constantly reminding them of their sins and shortcomings (Revelation 12:10). He accused Job of loving God only for His blessings, but Job's faith proved otherwise (Job 1:9–11). Satan continues to accuse people today. His accusations are described as deceitful and rooted in lies, aiming to make believers doubt God's grace and forgiveness (John 8:44) or to fill people with guilt and shame. However, Satan's accusations are powerless against the saving work of Jesus Christ, who intercedes for believers and assures them of their place in God’s family (1 John 2:1–2; Romans 8:33–35). Ultimately, Satan’s accusations will be silenced forever when he is cast into the lake of fire (Revelation 20:10).
Satan wants us to be fearful and doubt our salvation. When the temptation to doubt comes, we need to change our focus and look to Christ instead: "let us also lay aside every weight, and sin which clings so closely, and let us run with endurance the race that is set before us, looking to Jesus, the founder and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God" (Hebrews 12:1–2). Our salvation comes from God alone and nothing that Satan says can change that (Ephesians 2:8–9; Romans 8:31–39; John 10:27–30).
It is only through putting our faith in Jesus' sacrifice that we are able to receive God's everlasting grace and mercy. Upon salvation, we are added into His family (John 1:12). The Lord is the one who justifies us; He loves us faithfully and unconditionally; and His mercies for us are new every morning (Romans 8:33; Lamentations 3:22–23). Yes, Christians will continue to sin, but when we do, we know that Jesus forgives us and is faithful to cleanse us (1 John 1:9; 2:1). Note that the conviction of sins from the Holy Spirit is different from the accusations of Satan. The Holy Spirit convicts us of sin to draw us to God, where we find life. The Holy Spirit shines light into darkness. Satan accuses us of sin to keep us stuck in sin or to make us despair of ever being right before God. He accuses us before God to try to get God to renege on His forgiveness. But God is unchanging and absolutely faithful; His promises are true (2 Corinthians 1:19–22).
When we have been cleansed in Jesus Christ, we have no need to walk in shame. Satan has nothing left to accuse us of because it has been covered by Jesus' blood shed for us on the cross. Hebrews 7:25 assures us, "Consequently, he [Jesus] is able to save to the uttermost those who draw near to God through him, since he always lives to make intercession for them." We can trust the promises of God. He is faithful and true, and His Word holds power over any accusation the enemy might bring.