"In the flesh itself, the faith in His resurrection saves and justifies us. For, 'If you believe,' Paul says, 'in your heart that God raised him from the dead, you will be saved.' (Rm 10:9); and again, 'Who was delivered,' he says, 'for our offenses, and was raised again for our justification' (Rm 4:25). So the reward of our faith is the resurrection of the body of our Lord.

"For even His enemies believe that that flesh died on the cross of His passion, but they do not believe it to have risen again. Believing this most firmly, we gaze upon it as from the solidity of a rock: from which we wait with certain hope for the adoption; the redemption of our body (Rm 8:23); because we hope for that in the members of Christ, that is, in ourselves, which by a sound faith we acknowledge to be perfect in Him as in our Head. So it is that He would not have His back parts seen except as He passed by, that His resurrection may be believed. For that which is Pascha in Hebrew, is translated Passover [or a 'passing by']. As John the Evangelist also says, 'Now before the Feast of the Passover, when Jesus knew that his hour had come to depart out of this world to the Father' (Jn 13:1)."

Augustine, On the Trinity, 2.17