How do we know Jesus' sacrifice atoned for our sins?

The assurance of Christ's atonement is backed by biblical text, particularly in Hebrews 10:10 and 10:14, which state that by the will of God, we are sanctified through the offering of the body of Jesus Christ once for all. This underscores the completion and sufficiency of Christ's sacrifice. Unlike the repeated sacrifices of the Old Testament, which could not fully remove sin, Christ's single offering has perfected forever those who are sanctified. Therefore, He effectively dealt with sin for His people, demonstrating that His sacrifice was not only sufficient but complete.