In the first-century CE exegetic Vimuttimagga, Arahant Upatissa identifies the need to find a "good friend" or "pre-eminent friend" in order to develop "excellent concentration."
In the fifth-century CE Visuddhimagga ("Path of Purification"), Buddhaghosa also mentions the need to find a "good friend" in the context of finding one who will be your "giver of a meditation subject."[REF]