"A brother asked Abba Sisoes the Theban, 'Give me a word,' and he said, 'What shall I say to you? I read the New Testament, and I turn to the Old.'"
Abba Sisoes 35 (PG 65, col. 404). This one doesn't appear in the Collection systématique (SC 387, 474, and 498), or, at least, not in the Concordance (SC 498, pp. 217 ff.) under Sisoès. The desert Christian: sayings of the Desert Fathers: the alphabetical collection, trans. Benedicta Ward (New York, NY: Macmillan Publishing Co., Inc., 1975), 219 (ἀναγινώσκω, ἀνακάμπτω).