Ibn Nuaim reported: Sufyan Ath-Thawri, may Allah have mercy on hIm. would say, "If a man intended to write the hathh, he would study good manners and worship for twenty years before doing so."

Source: HIIyat aI Awliya 361

Ibn Al Mubarak, may Allah have mercy on him, said, "I sought manners for thirty years and I sought knowledge for twenty years. The righteous predecessors would seek manners and then seek knowledge."

Source: Ghayat al Nihayah 1/446