It is narrated from Abu al-Juwayriyah that he said: I heard a Bedouin from Banu Sulaym ask Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) about stray animals: What is your view about stray animals? He said: Whoever eats from stray animals is astray. He asked again: What is your view about stray animals? He said: Whoever eats from stray animals is astray. Then the man fell silent, and Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) became busy giving rulings to the people — Abu al-Juwayriyah says: many rulings which I could not memorise. Then the Bedouin said: I see that you have answered all the people except me; do you think I will get a turn? Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: Woe to you! Do not ask this question. And he said: How grave your question is! And he said: Seek Allah's forgiveness, turn to Him, and regard what you have done as a grave matter. (Then) he said: Do you know concerning what this verse was revealed: "O you who believe, do not ask about things which, if they were made plain to you, would trouble you" [Surah al-Ma'idah: 101]? When he had finished reciting the verse, he said: People used to ask the Messenger of Allah (peace and blessings be upon him) questions mockingly. A man would say: Who is my father? And a man whose she-camel had strayed would say: Where is my she-camel? So Allah Almighty revealed this verse concerning it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12076