Musnad Ahmad 25:50

Ibn Abi ‘Adi narrated to us, from Sa‘id, and Ibn Ja‘far narrated to us, Sa‘id narrated the meaning, and Ibn Abi ‘Adi said: From Sa‘id, from Abu Yazid, from ‘Ikrimah, from Ibn ‘Abbas, who said: "The Prophet of Allah, may Allah bless him and grant him peace, would recite in prayers, and he would remain silent, so we recite in what the Prophet of Allah recited in, and we remain silent in what he remained silent in." It was said to him: "Perhaps he was reciting to himself?" He became angry at that and said: "Do you accuse the Messenger of Allah, may Allah bless him and grant him peace?" And Ibn Ja‘far and ‘Abd al-Razzaq said: "Do you accuse the Messenger of Allah?"