Musnad Ahmad 31:742

'Affan narrated to us, Wuhayb narrated to us, Yahya ibn Sa'id narrated to us, from 'Abdullah ibn 'Abd al-Rahman al-Ansari, from Nahar al-'Abdi, from Abu Sa'id al-Khudri, from the Prophet, peace and blessings of Allah be upon him, who said: "Indeed, Allah will ask the servant on the Day of Resurrection, to the point that He will ask him, saying: 'O My servant, you saw a wrong, yet you did not forbid it.' Then, when Allah instructs a servant in his plea, he will say: 'O my Lord, I trusted in You, and I feared the people.'"