Musannaf Ibn Abi Shayba 33:951

Al-Muharibi narrated to us, from Abd al-Rahman ibn Sulayman al-Absi, from Idris ibn Sinan, from his grandfather Wahb ibn Munabbih, who said: Upon Musa, on the day he conversed with his Lord at the tree, was a jubbah (outer garment) of wool, trousers of wool, and a cap of wool.