How do we know Christ is the rightful mediator?

Christ is established as the rightful mediator due to His unique qualifications. First, He is fully God and fully man, enabling Him to represent both parties perfectly. Hebrews 4:15 tells us that Christ was tempted in every way as we are, yet without sin. Secondly, He is appointed by God Himself, which affirms that humanity's salvation rests not on human choice but on divine initiative. The profound assurance that Christ, as our representative, accomplished what is required for our salvation—the satisfaction of God’s justice through His death—further emphasizes the necessity of His mediatorial work. It is through His righteousness, imputed to believers, that we can stand before God.