I am seeing this saying quoted quite often nowadays, that is attributed to Hazrat Ali (R.A.)
If you cannot prevent an oppression, at least announce it to everyone?
Does this saying really belong to Hazrat Ali (R.A.)? If so, where is it documented, and can you also include original Arabic saying?
If not, does this saying belong to another credible Islamic figure?
When you see something bad happening then stop it by hand or stop it by talk or just think it bad.