How do we know that Christ's atonement is effective?

The effectiveness of Christ's atonement lies in the concept of substitution. As articulated in the sermon, the cardinal fact of the gospel is that Christ suffered as our substitute, taking upon Himself the punishment for the sins of His people. This is rooted in passages such as 2 Corinthians 5:21, which states that He became sin for us, so that we might become the righteousness of God in Him. The assurance of our salvation rests on the belief that Christ's sacrifice was sufficient and fully satisfying to God’s justice. It was specifically for those whom the Father chose, establishing His purpose and demonstrating His love in calling sinners to Himself.