How do we know that salvation is accomplished through Jesus?

The doctrine of salvation in historic Reformed theology teaches that Jesus Christ is both the High Priest and the Lamb of God. In John 17:12, Jesus states that He has kept those whom the Father gave Him, emphasizing that His sacrificial work is not for everyone but specifically for the elect. Hebrews 9:12 states, 'Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.' This demonstrates the assurance of salvation for those who believe, as Christ has finished the work necessary for our redemption, guaranteeing security for believers through His righteousness.