Then the seventy returned with joy, saying, “Lord, even the demons are subject to us in Your name.” And He said to them, “I saw Satan fall like lightning from heaven. Behold, I give you the authority to trample on serpents and scorpions, and over all the power of the enemy, and nothing shall by any means hurt you. Nevertheless do not rejoice in this, that the spirits are subject to you, but rather rejoice because your names are written in heaven.” (Luke 10:17–20)
The authority, however, which they bore to reprove evil spirits, and the power of crushing Satan, was not given them that they might themselves so much be regarded with admiration, as that Christ might be glorified by their means, and be believed on by those whom they taught, as by nature God, and the Son of God; and invested with so great glory and supremacy and might, as to be even able to bestow upon others the power of trampling Satan under their feet.
But they, it says, in that they were counted worthy of so great grace, “returned rejoicing, and saying, Lord, even the demons are subject to us in Your name.” For they confess the authority of Him Who honored them, and wonder at the supremacy and greatness of His power. But they seem to have rejoiced, not so much because they were ministers of His message, and had been counted worthy of apostolic honors, as because they had worked miracles. But it would have been better for them to have reflected, that He gave them the power to work miracles, not that they might be regarded by men with admiration on this account, but rather that what they preached might be believed, the Holy Spirit bearing them witness by divine signs. It would have been better, therefore, had they manifestly rejoiced on account of those rather who had been won by their means, and had made this a cause of exultation. Just as also the very wise Paul gloried in those who had been called by his means, saying, “My joy and my crown.” But they said nothing at all of this kind, but rejoiced only in that they had been able to crush Satan.
And what is Christ’s reply? “I saw Satan fall like lightning from heaven.” That is, “I am not unaware of this: for inasmuch as you set out upon this journey, so to speak, by My will, you have vanquished Satan. ‘I saw him fall like lightning from heaven.’” And this means that he was cast down from on high to earth: from overweening pride to humiliation: from glory to contempt: from great power to utter weakness. And the saying is true: for before the coming of the Savior, he possessed the world. All was subject to him, and there was no man able to escape the meshes of his overwhelming might. He was worshiped by every one. Everywhere he had temples and altars for sacrifice, and an innumerable multitude of worshipers. But because the Only-begotten Word of God has come down from heaven, he has fallen like lightning: for he who of old was bold and arrogant, and who contended with the glory of Deity; he who had as his worshipers all that were in error, is put under the feet of those that worshiped him.
Cyril of Alexandria, Commentary on the Gospel of St. Luke 64