Cyril of Alexandria
Catena Aurea · Lukasevangelium 17
And he said unto the disciples, The days will come, when ye shall desire to see one of the days of the Son of man, and ye shall not see it. And they shall say to you, See here; or, see there: go not after them, nor follow them. For as the lightning, that lighteneth out of the one part under heaven, shineth unto the other part under heaven; so shall also the Son of man be in his day. But first must he suffer many things, and be rejected of this generation.
When our Lord said, The kingdom of God is within you, He would fain prepare His disciples for suffering, that being made strong they might be able to enter the kingdom of God; He therefore foretells to them, that before His coming from heaven at the end of the world, persecution will break out upon them. Hence it follows, And he said unto the disciples, The days will come, &c. meaning that so terrible will be the persecution, that they would desire to see one of His days, that is, of that time when they yet walked with Christ. Truly the Jews ofttimes beset Christ with reproaches and insults, and sought to stone Him, and ofttimes would have hurled Him down from the mountain; but even these seem to be looked upon as slight in comparison of greater evils that are to come.