John Cassian, The Institutes V.28: The lesson and example which Abbot John when dying left to his disciples

When the same old man, as one who was readily going to depart to his own, was lying at his last gasp, and the brethren were standing round, they implored and intreated that he would leave them, as a sort of legacy, some special charge by which they could attain to the height of perfection, the more easily from the brevity of the charge: he sighed and said, “I never did my own will, nor taught any one what I had not first done myself.”