Safwan bin Amr said: I was at the door of Umar bin Abd al-Aziz (may Allah have mercy on him) when a horse came out towards us, on whose thighs was written: 'Uddatun lillah' (war equipment for Allah).
The Shaykh said: What is reported from Sayyiduna Ali (may Allah be pleased with him) concerning rikaz (buried treasure) has already been discussed in the Book of Zakah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13265