Jesus' sacrifice is effective because it completely pays the sin-debt of the elect, making them perfect before God (Hebrews 10:17).
The effectiveness of Jesus' sacrifice is rooted in its ability to satisfy God's justice while simultaneously justifying the ungodly. Hebrews 10:17 states that because of His one offering, God can deem the redeemed perfect and free from sin. This is a crucial part of the New Covenant, ratified in Christ's blood, where all who are in Him are assured of their standing before God. They are no longer condemned, as their sins have been completely dealt with, signifying the totality of the redemption accomplished through Christ's sacrifice; therefore, no further sacrifice is needed.
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