Thanks to Will at Prydain for posting this wonderful quote from Saint Augustine of Hippo:
Our Lord’s will has been to prefigure us, who are His body, in that Body of His in which He has already died and risen, and ascended into Heaven; that whither the Head has gone before, thither the members may trust to follow. Therefore He represented us in Himself, when He willed to be tempted by Satan. For in Christ you were tempted, since Christ had flesh for Himself from you, salvation from Himself for you; death for Himself from you, life from Himself for you; insults for Himself from you, honours from Himself for you; therefore temptation for Himself from you, victory from Himself for you. If in Him we have been tempted, in Him we overcome the devil. Do you observe that Christ was tempted, and not also that He conquered? Recognize yourself as tempted in Him, and recognize yourself as conquering in Him. (emphasis added)
–St. Augustine, on Psalm lx.