The height of being oppressed was displayed by Imam Hussain (AS) in Karbala. At that time Imam (AS) made a speech and asked: Who wants to help me?

Is there anyone who wants to help me? Only a very limited number among the Muslims of the time rushed to help Imam Hussain (AS) and gave their lives in the way of Allah (SWT) and were martyred with their leader, the Imam of the time. In the last hours of his life and before his martyrdom, Imam Hussain (AS) embraced his dear son Imam Sajjad (AS) and said: O’ my child, never be cruel or oppress a person who has no protector or help against you except Allah (SWT) [1]. (In fact Imam Hussain (AS) said this sentence for the attention of all Muslims and non-Muslims of the world throughout all eras, because Imams (AS) do not oppress anyone at any time.)

[1] Beharul Anwaar, Vol. 75, Page 118.

Source: en.shafaqna.com