How do we know Christ's sacrifice is sufficient?

The sufficiency of Christ's sacrifice is encapsulated in the doctrine of penal substitution, as seen in Hebrews 10:14, where it states that by one sacrifice, He has made perfect forever those who are being made holy. This sufficiency stems from the nature of Christ as both fully God and fully man, ensuring that His suffering was not only representative but also powerful enough to bear the weight of sin for all His people. The satisfaction of both the Father and the Son confirms that no further sacrifice is needed for redemption. When God raised Christ from the dead, it was His affirmation that Christ’s work of atonement had been fully completed, ensuring that all those for whom He died will certainly be saved.