It is narrated from Sayyiduna Duhak bin Sufyan that once a man from the tribe of Kilab asked him, "Duhak, what is your food?" He replied, "O Messenger of Allah! Meat and milk." The Prophet (peace and blessings be upon him) asked, "What does meat and milk become afterwards?" He replied, "You know that best." The Prophet (peace and blessings be upon him) said, "Allah has made the filth that comes out of the body of the son of Adam an example of this world."
Hadith Referenceمسند احمد / مسند المكيين / 15747
Hadith Gradingحکم دارالسلام:صحيح الغيره ، وهذا إسناد ضعيف لضعف على بن زيد، ولانقطاعه، فالحسن البصري لم يسمع من الضحاك بن سفيان