Of the essential manners of the believer is that of justice - a believer judges an action based on the action itself, and not who has done it.
In our latest episode (Episode 22), I discuss this reality and bring evidences from the Quran, the Sunnah and the lives of the Companions that demonstrate this.
The Quran explicitly commands us to be just, even if it be against our parents or with our enemies. And the Prophet (SAW) took the first Oath of Allegience at `Aqabah with the explicit command that the new converts must be just at all times.