On the Endless Kingdom:

Terrible in good truth is the judgment, and terrible the things announced. The kingdom of heaven is set before us, and everlasting fire is prepared. How then, some one will say, are we to escape the fire? And how to enter into the kingdom? I was an hungered, He says, and ye gave Me meat. Learn hence the way; there is here no need of allegory, but to fulfil what is said. I was an hungered, and ye gave Me meat; I was thirsty, and ye gave Me drink; I was a stranger, and ye took Me in; naked, and ye clothed Me; I was sick, and ye visited Me; I was in prison, and ye came unto Me. These things if thou do, thou shall reign together with Him; but if thou do them not, thou shalt be condemned. At once then begin to do these works, and abide in the faith; lest, like the foolish virgins, tarrying to buy oil, thou be shut out. Be not confident because thou merely possessest the lamp, but constantly keep it burning. Let the light of thy good works shine before men, and let not Christ be blasphemed on thy account. Wear thou a garment of incorruption, resplendent in good works; and whatever matter thou receivest from God to administer as a steward, administer profitably. Hast thou been put in trust with riches? Dispense them well. Hast thou been entrusted with the word of teaching? Be a good steward thereof. Canst thou attach the souls of the hearers? Do this diligently. There are many doors of good stewardship. Only let none of us be condemned and cast out; that we may with boldness meet Christ the Everlasting King, who reigns for ever. For He doth reign for ever, who shall be judge of quick and dead, because for quick and dead He died. And as Paul says, For to this end Christ both died and lived again, that He might be Lord both of the dead and living.

And shouldest thou ever hear any say that the kingdom of Christ shall have an end abhor the heresy; it is another head of the dragon, lately sprung up in Galatia. A certain one has dared to affirm, that after the end of the world Christ shall reign no longer; he has also dared to say, that the Word having come forth from the Father shall be again absorbed into the Father, and shall be no more; uttering such blasphemies to his own perdition. For he has not listened to the Lord, saying, The Son abideth for ever. He has not listened to Gabriel, saying, And He shall reign over the house of Jacob for ever, and of His kingdom there shall be no end. Consider this text. Heretics of this day teach in disparagement of Christ, while Gabriel the Archangel taught the eternal abiding of the Saviour; whom then wilt thou rather believe? Wilt thou not rather give credence to Gabriel? Listen to the testimony of Daniel in the text; I saw in a vision of the night, and behold, one like the Son of Man came with the clouds of heaven, and came to the Ancient of days. .... And to Him was given the honour, and the dominion, and the kingdom: and all peoples, tribes, and languages shall serve Him; His dominion is an everlasting dominion, which shall not pass away, and His kingdom shall not be destroyed. These things rather hold fast, these things believe, and east away from thee the words of heresy; for thou hast heard most plainly of the endless kingdom of Christ.

ST. CYRIL OF JERUSALEM (CATECHETICAL LECTURES, LECTURE XV., Verses 26-27, On DANIEL vii. 9--14)