The atonement as the keystone of an arch
Driving home: If you touch the keystone, you destroy the building itself.
Picture an arch — every stone matters, but the keystone is the central one. Touch the keystone and the whole arch comes down. So Christ's atonement is the keystone of the Christian system: pull it out and everything else collapses.
The author is saying, here's the keystone. Picture an arch. The keystone is that central stone, which if we move the whole arch comes crumbling down. The author is saying that in that keystone, everything prior to it is bound up in the nature of the creature who was to be redeemed. That is, what man is as a creature and a sinner. And everything that Scripture teaches about the nature of the Redeemer.
5:44 - 6:12 Read in full sermon