Khalid bin Aslam said: We went out with Abdullah bin Umar (may Allah be pleased with them both), and while we were walking a Bedouin caught up with us and said: Are you Abdullah bin Umar? He said: Yes. The Bedouin said: I asked about you and was directed to you. Tell me: does the paternal aunt inherit? Ibn Umar (may Allah be pleased with them both) said: I do not know. He said: You are Ibn Umar and you do not know this? Another time he said: You do not know, and we do not know. Ibn Umar (may Allah be pleased with them both) said: Yes; go to the scholars of Madinah and ask them. When he turned away, Ibn Umar (may Allah be pleased with them both) kissed his own hands and said: How well Abu Abd al-Rahman spoke! He was asked about what he did not know, and he said: I do not know. Then the Bedouin said: Allah Almighty says: "And those who hoard gold and silver" [Surah al-Tawbah: 34]. Abdullah bin Umar (may Allah be pleased with them both) said: Whoever hoarded them and did not pay their zakah, woe to him. This was only before the command of zakah was revealed; when zakah was revealed, Allah Almighty made it a means of purifying wealth. Then he looked towards me and said: I would not mind if I had gold equal to (Mount) Uhud, knowing its amount, paying its zakah and dealing with it in obedience to the command of Allah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7229