How much more shall the blood of Christ, who through the eternal Spirit offered Himself without spot to God, cleanse your conscience from dead works to serve the living God?
Our safety in Christ results from “the answer of a good conscience toward God” (1 Pet. 3:21). The Greek word for “answer” refers to a pledge, in this case agreeing to meet certain conditions required by God before being placed into the ark of safety (Christ).
Unregenerate men and women have consciences that condemn them. One who appeals to God for a good conscience is sick of his sin and desires to be delivered from the load of guilt he bears. He has a crushing and intimidating fear of coming judgment and knows only God can deliver him. He desires the cleansing that comes through the blood of Christ (cf. Heb. 10:22). So he repents of his sin and pleads for forgiveness.
When Christ suffered on the cross, hell threw all its fury at Him, and wicked men vented their hatred on Him. Yet through that suffering, He served as an ark of safety for the redeemed of all ages. And because He triumphantly provided salvation through His suffering, we are safe in Him.