According to Shi’a Islam the second fundamental pillar is Justice. It means that Allah (swt) is equitable and fair.
In this regards we have the comments of Shaykh Saduq who wrote in ‘A Shi’ite Creed’ the English translation of I'teqadat-Al-Imamiah page 65:
Verily Allah, Who is Blessed and Exalted above all others, has commanded us to be just, while He Himself treats us with something even better, namely grace (tafaddul). And that is because He the Glorious and Mighty says:
“Whoso bringeth a good deed will receive tenfold the like thereof, while whoso bringeth an evil deed will be awarded the like thereof; and they shall not be wronged” Al-Qur'an 6:160
Justice (al-‘adl) means that He requites a good act with a good act and an evil act with an evil act. The Prophet (s) said: No man ever enters Paradise by virtue of his (good) actions (alone), except by the Mercy of Allah the Glorious and Mighty”
Allah (swt) does not perpetuate injustice towards his Servants. He (swt) is not cruel, He (swt) possesses infinite wisdom and all that He (swt) does, is for the betterment of humanity. The intentions of Allah (swt) are always correct and it is on account of this that human beings benefit from the favors that he (swt) showers upon them. Whatever He (swt) does is beneficial for his servants. This theory is clear and it is based on a solid foundation. Cruelty is a serious fault and we cannot accept that the Master of Creations would inflict cruelty on his subjects. When Allah (swt) does not want any human to be cruel why would he himself indulge in such activity? The roots of cruelty from:
Ignorance A situation when one feels that a matter is getting out of his hands so he resorts to cruelty to keep a grip on the situation.
When the entire content of the universe belongs to Allah (swt) how can he envisage losing anything? When Allah (swt) gives something to his subject, it is due to the fact that this individual is a special person / who has been awarded for an exemplary deed.
If Allah (swt) punishes someone it is on account of his deeds no blame can be attributed to the Creator. Everything that Allah (swt) does is based upon wisdom. Even if we come across a situation that on the face of it seems detrimental, there is always a good reason behind it.
The rationale mind is receptive to the idea that Allah (swt) is just. No rationale minded individual would entertain the thought that that Allah (swt) perpetuates injustice and cruelty against his creation. All that Allah (swt) does is based upon wisdom and is done so in his servant’s interests.
The justice of Allah (swt) can be ascertained from at least forty verses of the Qur’an. Whilst other religions believe that Allah (swt) is just, it is only the school of the Ahl’ul bayt (as) that holds this belief to be a core component of aqeedah. Both Christianity and Judaism deem GOD to be cruel (GOD FORBID), for example we read in the Old Testament, Exodus 34:7
”Keeping mercy for thousands, forgiving iniquity and transgression and sin, and that will by no means clear the guilty; visiting the iniquity of the fathers upon the children, and upon the children's children, unto the third and to the fourth generation”.
This verse depicts Allah (swt) as cruel, parents do bad deeds and yet their offspring shall be punished for their sins, down until the fouth generation. Compare this to the Justice of Allah (swt) in the Holy Quran, wherein it stated clearly that on the Day of Judgement we shall be adjudicated for our personal deeds NOT the deeds of others.
Muslims who believe that God creates evil have a similar type of thinking. In (Sifate-e-Iman Mufasil) we read that evil and good comes from Allah (swt), it is indeed unfortunate that the proponents of this thinking fail to contemplate that the root cause of evil is cruelty. If we believe this concept then we are in effect stating that Allah (swt) is the cruelest entity. When Allah (swt) is cruel what should we expect from his creation? To suggest that Allah (swt) is unjust is without foundation and tantamount to kufr.
The logical mind is more prepared to accept Allah (swt) the sublime Creator is just, and the religion of Ahl’ul bayt (as) tells us that Allah (swt) has no partner, and he is filled / endowed with infinite justice.