Musnad Ahmad 329:33

Surayj ibn al-Nu'man narrated to us, he said: 'Abd al-'Aziz al-Darawardi narrated to us, from 'Umarah ibn Ghaziyyah, from 'Abbad ibn Tamim, from his uncle 'Abdullah ibn Zayd: "That the Messenger of Allah (peace and blessings of Allah be upon him) sought rain while he was wearing a black khamisah (garment) of his. He intended to take its lower part and place it over its upper part, but it was heavy for him, so he turned it over, [placing] its right side over its left, and its left side over its right."