On the authority of Abu Sa'id (may Allah be pleased with him), who said that the Messenger of Allah (may the blessings and peace of Allah be upon him) said:
Let not any one of you belittle himself. They said: O Messenger of Allah, how can any one of us belittle himself? He said: He finds a matter concerning Allah about which he should say something, and he does not say (it), so Allah (mighty and sublime be He) says to him on the Day of Resurrection: What prevented you from saying something about such-and-such and such-and-such? He says: {It was} out of fear of people. Then He says: Rather it is I whom you should more properly fear.
It was related by Ibn Majah with a sound chain of authorities.
