Musannaf Ibn Abi Shayba 21:663

'Abd al-Wahhab al-Thaqafi narrated to us, from Khalid, who said: I was at the funeral of Ghunaym, and a man among them narrated to me that he said: I heard Abu Musa pray over a dead person, so he said the takbir and then said: "O Allah, forgive him just as he sought Your forgiveness, and give him what he asked of You, and increase him from Your bounty."