How do we know that Christ's sacrifice was sufficient for all believers?

The sufficiency of Christ's sacrifice is rooted in the biblical assurances that He died specifically for His people, as noted in Isaiah 53 where it mentions, 'He shall see of the travail of his soul, and shall be satisfied.' This indicates that His atoning work has fully met the requirements for salvation for those He chose. Moreover, Hebrews 9:12 affirms that 'by his own blood he entered in once into the holy place, having obtained eternal redemption for us.' This means that Christ's atonement is not only sufficient but also effective, securing eternal life for all those whom He calls. The assurance of this truth undergirds the faith of believers, reminding us that our salvation rests firmly in His completed work, not our own merit.