Ghaylan (may Allah have mercy on him) narrates from Sayyiduna Anas (may Allah be pleased with him) that he said: You do many deeds that are finer than a hair in your eyes, whereas in the time of the Prophet (peace and blessings be upon him) we used to count them among the things that destroy.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20761