Musannaf Ibn Abi Shayba 29:137

Ibn Numayr narrated to us, from Thawr, from Ziyad ibn Abi Sawdah, from Abu Maryam, who said: When he came to Ash-Sham, he came to the Mihrab of Dawud and prayed in it. He recited Surah Sad, and when he reached the prostration, he prostrated.