Musannaf Ibn Abi Shayba 24:61

Muhammad ibn Bishr narrated to us, he said: I heard Humayd ibn Abd al-Rahman al-Asamm mentioning from Umm Rashid, his grandmother, who said: I was with Umm Hani when Ali came to her, and food was called for him. She said: I went down and met two men in the courtyard, and I heard one of them saying to his companion: "Our hands have pledged allegiance to him, but our hearts have not pledged allegiance to him." She said: I said, "Who are these two men?" They said, "Talha and al-Zubayr." She said: I heard one of them saying to his companion: "Our hands have pledged allegiance to him, but our hearts have not pledged allegiance to him." Then Ali said: "And whoever breaks his pledge, breaks it only to his own detriment; and whoever fulfills that which he has covenanted with Allah, He will give him a great reward."