Musannaf Ibn Abi Shayba 3:2443

Waki’ ibn al-Jarrah narrated to us, he said: Sufyan narrated to us, from Habib ibn Abi Thabit, from ‘Ata’ ibn Abi Rabah, that a man greeted Ibn ‘Abbas while he was in prayer, so he took his hand and shook it, and squeezed his hand.