How do we know the doctrine of eternal redemption is true?

The doctrine of eternal redemption is grounded in the New Testament, especially in the book of Hebrews. As Hebrews 9 explains, Christ's blood, being of infinite worth, secures eternal redemption for His people, contrasting the temporary sacrifices of the Old Testament that couldn't fulfill God's requirement for holiness. The author of Hebrews emphasizes that this new covenant established by Christ offers a permanent solution for sin and purifies our conscience, indicating that our relationship with God is now secure. This is corroborated by other writings in Scripture, such as Ephesians 1:7, which states that in Christ we have redemption through His blood, the forgiveness of our trespasses. Hence, the consistency of this truth throughout Scripture reinforces its validity.