Sayyidah Duba'ah bint al-Zubayr bin Abd al-Muttalib (may Allah be pleased with her) said: Sayyiduna al-Miqdad (may Allah be pleased with him) went to al-Baqi' to relieve himself, and he saw a rat bringing a dinar out of a hole. It kept bringing out dinars one by one until it had brought out seventeen dinars. Then it brought out a piece of red cloth with a dinar in it, so they became eighteen dinars. He took them to the Prophet (peace and blessings be upon him), told him the whole story and said: Take the zakah of it. The Prophet (peace and blessings be upon him) said: "Did you bend down to the hole (to search in it)?" He said: No. So the Messenger of Allah (peace and blessings be upon him) said: 'Baraka Allahu laka fiha' (May Allah bless you in them).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7651