It was narrated from Abu Sa’eed Al-Khudri that the Messenger of Allah ﷺ stood up to deliver a sermon, and one of the thing that he said was: “No,fear of people should prevent a man from speaking the truth, if he knows it. Then Abu sa’eed wept and said: By Allah, we have seen things that made us scared (and we did not speak up).” (Sahih)