How do we know that Christ's sacrifice provides us with eternal life?

According to Romans 5:10 and 6:23, the death of Christ reconciles us to God and bestows upon us the gift of eternal life. When Christ died, He took our death, and in return, He grants us everlasting life. This divine exchange underlines the doctrine of justification, where we are declared righteous based solely on Christ's finished work. The ultimate assurance of this promise comes from His resurrection, confirming that death has been defeated and believers in Him will have eternal life with Him.