Musnad Ahmad 26:835

Ya'qub narrated to us, my father narrated to us, from Ibn Ishaq, he said: And Abd al-Rahman ibn al-Aswad ibn Yazid al-Nakha'i narrated to me, from his father, he said: I and my uncle Alqamah entered upon Abdullah ibn Mas'ud at midday. He said: "He stood up for the Dhuhr prayer to pray, so we stood behind him. He took my hand and my uncle's hand, then he placed one of us on his right and the other on his left, then he stood between us, and we formed a single row behind him." He said: Then he said: "This is how the Messenger of Allah, peace and blessings of Allah be upon him, used to do when there were three." He said: So he led us in prayer. When he bowed, he placed his hands together (tatbiq), pressed his forearms against his thighs, and inserted his palms between his knees. He said: When he finished the prayer, he turned to us and said: "There will be leaders who will delay the prayer from its appointed times. If they do that, do not wait for them to pray it, and make the prayer with them a voluntary prayer (subhah)."