“Let not any one of you belittle himself.” They said: “O Messenger of Allah, how can any one of us belittle himself?” He صلى الله عليه وسلم said: “He finds a matter concerning Allah about which he should say something, and he does not say it, so Allah سبحانه وتعالى says to him on the Day of Resurrection: ‘What prevented you from saying such-and-such and such-and-such?’ He says: “It was out of fear of people.” Then He سبحانه وتعالى says: “Rather it is I whom you should more properly fear.”

On the authority of Abu Said رضي الله عنه who said that the Messenger of Allah صلى الله عليه وسلم said:

“Let not any one of you belittle himself.” They said: “O Messenger of Allah, how can any one of us belittle himself?” He صلى الله عليه وسلم said: “He finds a matter concerning Allah about which he should say something, and he does not say it, so Allah سبحانه وتعالى says to him on the Day of Resurrection: ‘What prevented you from saying such-and-such and such-and-such?’ He says: “It was out of fear of people.” Then He سبحانه وتعالى says: “Rather it is I whom you should more properly fear.”

Ibn Majah