John Cassian, The Institutes IV.25: Of the unique vase of oil thrown away by Abbot John at his senior's command

Thus the youth, trained up by exercises of this sort, daily increased in this virtue of obedience, and shone forth more and more with the grace of humility; and when the sweet odour of his obedience spread throughout all the monasteries, some of the brethren, coming to the elder for the sake of testing him or rather of being edified by him, marvelled at his obedience of which they had heard; and so the older called him suddenly, and said, “Go up and take this cruse of oil” (which was the only one in the desert and which furnished a very scanty supply of the rich liquid for their own use and for that of strangers) “and throw it down out of window.” And he flew up stairs when summoned and threw it out of window and cast it down to the ground and broke it in pieces without any thought or consideration of the folly of the command, or their daily wants, and bodily infirmity, or of their poverty, and the trials and difficulties of the wretched desert in which, even if they had got the money for it, oil of that quality, once lost, could not be procured or replaced.