Musannaf Ibn Abi Shayba 21:217

Waki’ narrated to us, from al-A’mash, from Abu al-Duha, from Masruq, who said: We were with Abu Musa. We came at night to a ruined orchard. He said: He stood up at night to pray, and he recited with a beautiful recitation. Then he said: "O Allah, You are the Faithful (Mu'min), You love the faithful; and the Guardian (Muhaymin), You love the guardian; the Peace (Salam), You love peace; the Truthful (Sadiq), You love the truthful."