The Messenger of Allah ﷺ said, "Let no man be prevented by fear of others from speaking up for the truth, once he knows it."
حدثنا خلف بن الوليد حدثنا عباد بن عباد حدثنا المعلى بن زياد القردوسي عن الحسن
قال رسول الله ﷺ ألا لا يمنعن رجلا رهبة الناس إن علم حقا أن يقوم به
Its chain of transmission is sahih. Mualla bin Ziyad Firdawsi Basri has come up frequently before, and he is truthful and ascetic. The hadith has already appeared at 10959.