How do we know Christ's sacrifice is sufficient for salvation?

The assurance of Christ’s sufficiency in His sacrifice is rooted in the teaching of Scripture that emphasizes His atoning work as intentional and accomplished. For instance, Acts 20:28 declares that the Church is purchased with His own blood, affirming the completeness of this transaction. Without the shedding of blood, there is no forgiveness (Hebrews 9:22), which indicates that Christ's death was necessary for securing salvation. Furthermore, John 10:28 reveals that all given to Him will not be lost, highlighting the efficacy of Christ's work and His role as the Good Shepherd who ensures the safety and sustenance of His flock.