How do we know the sacrifice of Christ is effective?

The effectiveness of Christ's sacrifice can be confirmed through Scriptures such as Hebrews 9:28, which states that Christ was offered once to bear the sins of many. His sacrifice was not merely symbolic; it accomplished the complete removal of sin and satisfied God's justice. When God looks at His people, He sees the righteousness of Christ instead of their sins, a fulfillment of the promise that their iniquities would be remembered no more (Hebrews 10:17). This assurance allows believers to rest in the knowledge that their salvation is secured in the efficacy of Christ's atonement.