How do we know the effectiveness of Christ's sacrifice?

The effectiveness of Christ's sacrifice is assured through His resurrection, which signifies that His atonement was accepted by God. After bearing the sins of many and facing the judgment for those sins, Christ's resurrection conveys the truth that death could not hold Him, as He had fulfilled the requirements of divine justice. As mentioned in Hebrews, He offered Himself once, which underscores the finality and sufficiency of His sacrifice. This assurance provides believers with confidence in their salvation and the transformative power of His grace.