How do we know that salvation is effective through Christ?

The effectiveness of salvation through Christ is supported by scripture, including Acts 4:12, which declares that 'Neither is there salvation in any other.' This indicates that apart from Christ, there is no possibility of redemption. In Hebrews 10:14, we read that 'by one offering he hath perfected forever them that are sanctified,' pointing to the sufficiency and finality of Christ's sacrifice. His obedience fulfills the law, satisfying God's justice and demonstrating God's grace in selecting those who would be redeemed. Furthermore, the assurance of salvation is rooted in God's unchanging purpose, as noted in Ephesians 1:4-5, showing that it was planned before the foundation of the world.