How do we know our sins are forgiven according to the Bible?

Jesus’ declaration to the paralyzed man, 'Son, be of good cheer; thy sins be forgiven thee' (Matthew 9:2), directly affirms the believer's forgiveness. This is not based on our merit but on faith in Christ's atonement. Additionally, Romans 5:1 states that, 'being justified by faith, we have peace with God through our Lord Jesus Christ,' highlighting that faith in Him secures our standing before God. The believer's assurance is rooted in the unchanging nature of God's promises and the sufficiency of Christ’s sacrifice.