Musannaf Ibn Abi Shayba 3:1576

Yahya ibn Sa'id narrated to us, from 'Abdullah ibn al-'Aizar, who said: I was performing Tawaf with Sa'id ibn Jubayr, and he saw a man praying, placing one of his hands upon the other—this one upon this one, and this one upon this one. So he went and separated them, then he came back.