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

The sufficiency of Christ's atonement is demonstrated through His perfect obedience and sacrificial death, which is the only remedy for sin. Scripture teaches that He bore the sins of His people, satisfying God's wrath and securing redemption through His sacrifice (1 John 4:10). The Lord Jesus declared from the cross, 'It is finished,' signifying that His work of atonement was complete and effective for those He represented (John 10:15). Those for whom Christ died are justified freely by God's grace and granted eternal life, which points to the completeness and sufficiency of His redemptive work.