Origen

Yet shall the generation of the Church survive the whole of this world, that it may inherit the world to come, yet it shall not pass away until all these things have come to pass. But when all these shall have been fulfilled, then not the earth only but the heavens also shall pass away; that is, not only the men whose life is earthy, and who are therefore called the earth, but also they whose conversation is in heaven, and who are therefore called the heaven; these shall pass away to things to come, that they may come to better things. But the words spoken by the Saviour shall not pass away, because they effect and shall ever effect their purpose; but the perfect and they that admit no further improvement, passing through what they are, come to that which they are not; and this is that, My words shall not pass away. And perhaps the words of Moses and the Prophets have passed away, because all that they prophesied has been fulfilled; but the words of Christ are always complete, daily fulfilling and to be fulfilled in the saints. Or perhaps we ought not to say that the words of Moses and the Prophets are once for all fulfilled; seeing they also are the words of the Son of God, and are fulfilled continually.