It is narrated from Sayyiduna Fadalah bin Ubayd (may Allah be pleased with him) that he heard the Prophet (peace and blessings be upon him) saying: "Successful is the one who was guided to Islam, whose livelihood is just sufficient for his needs (kafaf), and who is content with it." This hadith has an authentic (sahih) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.