Now this is a proof that Christ is God the Word, and the Power of God. For whereas human things cease, and the Word of Christ abides, it is clear to all eyes that what ceases is temporary, but that He Who abides is God, and the true Son of God, His only-begotten Word.
-St. Athanasius of Alexandria, On the Incarnation 55, 4th Century


But why did He appear not to all, but to the Apostles only? Because to the many it would have seemed a mere apparition, inasmuch as they understood not the secret of the mystery For if the disciples themselves were at first incredulous and were troubled, and needed the evidence of actual touch with the hand, and of His eating with them, how would it have fared in all likelihood with the multitude? For this reason therefore by the miracles [wrought by the Apostles] He renders the evidence of His Resurrection unequivocal, so that not only the men of those times-- this is what would come of the ocular proof--but also all men thereafter, should be certain of the fact, that He was risen. Upon this ground also we argue with unbelievers. For if He did not rise again, but remains dead, how did the Apostles perform miracles in His name? But they did not, say you, perform miracles? How then was our religion instituted?
-St. John Chrysostom, Homily I on Acts I, 4th Century