Why is the concept of Christ's sacrifice foundational for salvation?

The message emphasizes that the cross of Christ is not only the beginning but also the foundation and culmination of our salvation. Before we engaged in any good work or had any awareness of our need, Christ was already slain for our sins. This understanding challenges us to recognize our dependence on Christ’s finished work for our assurance and security. Our faith rests solely on the justice and righteousness of God manifest in Christ's sacrifice, which secures our standing before Him for eternity.