Sayyiduna Ma'qil bin Yasar (may Allah be pleased with him) states: I was present with the Prophet (peace and blessings be upon him) together with Sayyiduna Abu Bakr (may Allah be pleased with him) (the narrator is in doubt, or perhaps the words are:) Sayyiduna Abu Bakr (may Allah be pleased with him) told me about the Prophet (peace and blessings be upon him) that he (peace and blessings be upon him) said: "Shirk among you is more hidden than the crawling of an ant. Then he said: Shall I not guide you to something that will remove its small and its great (that is, every kind of shirk)? Say: 'O Allah! I seek refuge in You from associating anyone with You while I know it, and I seek Your forgiveness for that of which I have no knowledge.'"
Abu Ya'la recorded it from his teacher Amr bin al-Husayn al-Uqayli, and he is matruk (abandoned).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الزهد / 17671