How do we know Jesus fulfills the role of the mediator?

In theological terms, Jesus fulfills the role of the mediator as He establishes a new covenant sealed by His blood, akin to the covenant God made with Noah after the flood. Noah's covenant marked a new beginning for humanity, while Christ’s new covenant brings everlasting life and restoration. Jesus explicitly refers to this new covenant during the Last Supper, emphasizing that His blood is shed for the salvation of many. Unlike Noah, whose mediation was restricted to a specific time and circumstance, Christ lives eternally as the mediator between God and humanity, offering access to God through grace. His work is perfect and complete, confirming our relationship with God through faith.