ייִדישער מחשבֿה אויף ישעיהו 50:7

Boldness is in place when one meets wicked people and transgressors and those who oppose the truth; and to exhort men to do kindness; and to warn people to avoid what is reprehensible. Boldness is proper to shame sinners and rebuke the small and the great, as it is said: "I have set my face like a flint" (Isaiah 50:7).

As the prophet wrote: "But the L-ord G-d helps me, therefore shall I not be confounded; therefore have I set my face like a flint, and I know that I shall not be ashamed" (Yeshaya 50:7), "Do not fear them or their words" (Yechezkel 2:6), "And you, son of man, fear them not, and fear not their words" (Yechezkel 2:6), "fear them not, neither shall you be intimidated by them" (Yechezkel 3:9).