Gregory the Great
Catena Aurea · Matthäusevangelium 16
For what is a man profited, if he shall gain the whole world, and lose his own soul? or what shall a man give in exchange for his soul? For the Son of man shall come in the glory of his Father with his angels; and then he shall reward every man according to his works. Verily I say unto you. There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
(ubi sup.) Or, by the kingdom of God is meant the present Church, and because some of His disciples were to live so long in the body as to behold the Church of God built up and raised against the glory of this world, this comfortable promise is given them, There be some of them standing here.