Musnad Ahmad 329:37

I read to Abd al-Rahman: Malik, and Ishaq narrated to us, he said: Malik narrated to me, from Abdullah ibn Abi Bakr, that he heard Abbad ibn Tamim saying: I heard Abdullah ibn Zayd al-Mazini saying: "The Messenger of Allah, peace and blessings of Allah be upon him, went out to the prayer ground and sought rain, and he turned his cloak when he faced the Qibla." Ishaq said in his narration: And he began with the prayer before the sermon, then he faced the Qibla and supplicated.