Musnad Ahmad 31:226

Ibn Numayr narrated to us, 'Ubayd Allah informed us, from 'Abd Allah ibn 'Abd al-Rahman ibn Ma'mar al-Ansari, from Nahar, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, one of you will be questioned on the Day of Resurrection, until it is among what he is questioned about that it is said: 'What prevented you from denouncing the evil when you saw it?'" He said: "So whoever Allah prompts with his argument, he will say: 'My Lord, I hoped in You, and I feared the people.'"