The life of St Pambo of Egypt
Early in his formation his own spiritual father gave him a single line from the Psalms concerning the guarding of one's own speech, and told him to make it his study; Pambo did not return for six months while he worked at it, and is said to have told other monks, even eighteen years afterward, that he still had not fully mastered that one line.
He lived on nothing but bread earned by his own hands, plaiting mats from rushes, and kept his speech so sparing that people sought him out for his silence nearly as often as for his words; asked once to offer some edifying word to the visiting Archbishop Theophilus, Pambo answered only that a man not edified by his silence would find no more in his speech. Athanasius, Melania the Elder, and Ammonas of Egypt all came to him for counsel, and he became in turn spiritual father to other saints, among them Pishoy and John the Dwarf.
Much of what survives of him comes down through Palladius's Lausiac History, with further mention in Jerome and Rufinus, an unusually well-attested memory for a desert father of his century.
