Musnad Ahmad 32:166

Yahya ibn Sa'id narrated to us, he said: Sa'id narrated to us, Qatadah narrated to us, that Anas ibn Malik narrated to them that the Prophet, peace and blessings of Allah be upon him, ascended Mount Uhud, and Abu Bakr, Umar, and Uthman followed him, and it shook beneath them. He said: "Be still, for upon you is a Prophet, a Truthful One (Siddiq), and two martyrs."