How do we know that Jesus' death provides eternal life?

The assurance of eternal life through Jesus’ death is foundational to Christian belief. In John 3:16, it is stated, 'For God so loved the world that he gave his only Son, that whoever believes in him should not perish but have eternal life.' This declaration shows that the outcome of faith in Christ is a direct result of His sacrificial death. His being lifted up is instrumental in satisfying God's justice — all sins of the elect were borne by Him, allowing for reconciliation between God and humanity. It is through this act of ultimate love that eternal life is secured for all who believe.