Musannaf Ibn Abi Shayba 3:163

Abu Bakr narrated to us, he said: Muhammad ibn Fudayl narrated to us, from al-A’mash, from Ibrahim, who said: Al-Aswad and Alqama entered upon Abdullah. Abdullah said: "Have these people prayed yet?" They said: "No." He said: "Then stand up and pray." He did not command an Adhan or an Iqamah. He stepped forward and led us in prayer. We went to stand behind him, but he took our hands and made us stand beside him. When we bowed, al-Aswad placed his hands upon his knees. Abdullah looked and saw him, so he struck his hand. Al-Aswad looked, and behold, Abdullah’s hands were between his knees, and he had interlaced his fingers. When he finished the prayer, he said: "If you are three, let one of you lead you. And when you bow, spread your forearms against your thighs; for it is as if I am looking at the interlacing of the fingers of the Prophet (peace be upon him) while he was bowing." Then he said: "There will be rulers who will cause the prayer to die—or he said: 'the worst of the dead'—and it is the prayer of one who is worse than a donkey, and the prayer of one who finds no alternative. So whoever among you reaches that time, let him pray the prayer at its appointed time, and let your prayer with them be a voluntary prayer (subhah)." I said to Ibrahim: "Did Alqama and al-Aswad do that?" He said: "Yes." I said to Ibrahim: "Do you do that?" He said: "Yes." I said: "Indeed, the people place their hands upon their knees." Ibrahim said: "I heard Abu Ma’mar say: 'I saw Umar placing his hands upon his knees.'"