“The world will not be destroyed by those who do evil, but by those who watch them without doing anything.” (Albert Einstein)

“The hottest place in Hell is reserved for those who remain neutral in times of great moral conflict…[an individual] who accepts evil without protesting against it is really cooperating with it” (Martin Luther King Jr.)

“If you are neutral in situations of injustice, you have chosen the side of the oppressor.  (Desmond Tutu)

In the End, we will remember not the words of our enemies, but the silence of our friends.  (Martin Luther King, Jr)

“The truth is like a lion; you don’t have to defend it. Let it loose; it will defend itself.”  (Augustine of Hippo)

Caliph Umar said to a congregation of Muslims gathered in a mosque near Jerusalem,
 "Speak the truth. Do not hesitate to say what you consider to be the truth. Say what you feel. Let your conscience be your guide. Let your intentions be good, for verily God is aware of your intentions. In your deeds your intentions count. Fear God, and fear no one else.”

If you don't speak out to warn the wicked to stop their evil ways, they will die in their sin. But I will hold you responsible for their death. If you warn the wicked and they do not turn from their wickedness or their evil ways, they will die because of their sin.   (Ezekiel 3:18-19)