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

The sufficiency of Christ's sacrifice for redemption is rooted in the concept of a one-time atonement as proclaimed in Hebrews 9:12, which states, 'By his own blood he entered once into the holy place, having obtained eternal redemption for us.' This signifies that Christ's blood is effective, complete, and final. Unlike the Old Testament sacrifices that required repeating annually, Christ's sacrifice was perfect and sufficient to cover all sins of those chosen by God. Thus, believers can rest assured in the certainty of their salvation through the grace bestowed upon them.