Musannaf Ibn Abi Shayba 3:1428

Yahya ibn Adam narrated to us, from Ammar ibn Ruzayq, from Abu Ishaq, from Abd al-Rahman ibn Awsajah, from al-Bara ibn Azib, from the Prophet, peace and blessings of Allah be upon him, who said: "Indeed, Allah and His angels send blessings upon the first rows."