The Shias believe that there is intrinsic good or evil in things, and that God commands them to do the good things and shun the evil. They believe that God acts according to a purpose or design, and human reason cannot comprehend this design or purpose in its entirety (though man must always strive to understand as much as he can).
The Sunni School of thought does not consider Justice of God as part of Uṣūl ad-Dīn (fundamentals of faith). It subscribes to the view that nothing is good or evil per se, and that what God commanded people to do became good by virtue of his command, and what he forbade became evil.
وَلََا يَظْلِمُ رَبكَ اََحَدًا
"....And your Lord does injustice to no one....."
Suratul Kahf 18:49 ‘Adl literally means to put everything in its rightful place. Sometimes ‘adl is confused with equality. Equality is not a condition for justice, e.g. Justice in a classroom does not mean that all the students are given equal marks; but that marks are given according to ability and effort. Similarly, it would not be ‘adl (justice) if a large oak tree was given the same roots as that of a small sapling. Adala is believing in nine things:
Allah is for all His creations a just Master.
Allah never does anything wrong (bad).
Allah does not fail to do anything that is necessary.
There is no injustice in Allah’s decisions.
When Allah tests us or gives a command,
. Allah will always reward those who obey.
. It is for Allah to decide if He so desires to punish.
Adhab will never go beyond what an individual deserves.
Allah does not force anyone to do evil and then punish him.
Believing in the ‘Adl (Justice) of Allah means that one should not be in a position of accusing Allah of injustice and favouritism. If Allah did something that was unfair, then 4 possibilities arise:
Allah does it knowingly - which would make Him Dhalim (Arabic: ظالم , "unjust") .
Allah does it unknowingly - which would make him Jahil (Arabic: جاهل , "ignorant")
Allah has been forced to do it - which makes Him Mohtaaj(Arabic: محتاج , "reliant on others")
Allah does it as an amusement - which does not make Him Hakim(Arabic: حکیم , "wise")