Musannaf Ibn Abi Shayba 33:1344

Muhammad ibn Abi Ubaydah narrated to us, he said: My father narrated to us, from al-A’mash, from ‘Amr ibn Murrah, from ‘Abd al-Rahman ibn Abi Layla, who said: What is it upon any one of you, when he is alone, to say to his two companions: "Listen, may Allah have mercy on both of you," and then dictate something good to them?