It hinges on the resurrection

But further: since Paul first expressed it, the Christian Church knows that everything depends on belief in the Resurrection. “If Christ hath not been raised, your faith is vain; ye are yet in your sins.” A Jesus who had not risen, who had remained in the grave, could not be the Christ. The Resurrection is the necessary vindication of His Messiahship. It is true that the disciples believed in Him as Messiah before His Resurrection; this comes out very clearly in Peter’s Confession at Caesarea Philippi. But this faith did not survive the terrible shock of Calvary. Without the fact of Easter the world would scarcely have heard either of a Church, or of Jesus Himself. It was the encounter with the Risen Lord which rescued the disciples from their perplexity and hopelessness, restored their broken faith, and more than this, filled them with jubilant certainty of victory, which was, and remained, the vital element in the Primitive Church, and gave the first Christians the power to be in the full difficult sense of the word “martyrs” for the truth of Christ.—Emil Brunner, The Christian Doctrine of Creation and Redemption, 366

<idle musing>
Indeed. Well, that's the final excerpt from vol. 2. I hope you enjoyed it as much as I did. I'm definitely going to read his third volume, but not right away. Hopefully I'll get around to it in the next year. Meanwhile, the next book in N. T. Wright, Simply Christian, his version of an apologetic for Christianity. After that, I'm not sure yet…
</idle musing>