He begins with the obvious:
Dead men cannot take effective action; their power of influence on others lasts only till the grave. Deeds and actions that energise others belong only to the living.
Ok. With you so far.
Well, then, look at the facts in this case. The Saviour is working mightily among men, every day He is invisibly persuading numbers of people all over the world, both within and beyond the Greek-speaking world, to accept His faith and be obedient to His teaching. Can anyone, in face of this, still doubt that He has risen and lives, or rather that He is Himself the Life?
Does a dead man prick the consciences of men, so that they throw all the traditions of their fathers to the winds and bow down before the teaching of Christ? If He is no longer active in the world, as He must needs be if He is dead, how is it that He makes the living to cease from their activities, the adulterer from his adultery, the murderer from murdering, the unjust from avarice, while the profane and godless man becomes religious? If He did not rise, but is still dead, how is it that He routs and persecutes and overthrows the false gods, whom unbelievers think to be alive, and the evil spirits whom they worship?
For where Christ is named, idolatry is destroyed and the fraud of evil spirits is exposed; indeed, no such spirit can endure that Name, but takes to flight on sound of it. This is the work of One Who lives, not of one dead; and, more than that, it is the work of God. It would be absurd to say that the evil spirits whom He drives out and the idols which He destroys are alive, but that He Who drives out and destroys, and Whom they themselves acknowledge to be Son of God, is dead.
In a word, then, those who disbelieve in the resurrection have no support in facts, if their gods and evil spirits do not drive away the supposedly dead Christ. Rather, it is He Who convicts them of being dead. We are agreed that a dead person can do nothing yet the Saviour works mightily every day, drawing men to religion, persuading them to virtue, teaching them about immortality, quickening their thirst for heavenly things, revealing the knowledge of the Father, inspiring strength in face of death, manifesting Himself to each, and displacing the irreligion of idols ; while the gods and evil spirits of the unbelievers can do none of these things, but rather become dead at Christ's presence, all their ostentation barren and void.
(Athanasius, On the Incarnation, ch 5)