Is the justice of Allah valid only for Muslims; or is it also valid for non-Muslims?
The justice of Allah is valid for everybody, whether Muslim or not. Allah has rendered it haram to commit injustice and oppression to people regardless of their religion. Is it possible for Allah, who renders it haram for people to commit injustice and oppression to others, to oppress people by abandoning justice?
It is emphasized by the phrase “nor is thy Lord ever unjust (in the least) to His servants” in the following verse: “Whoever works righteousness benefits his own soul; whoever works evil, it is against his own soul: nor is thy Lord ever unjust (in the least) to His servants”(Fussilat, 41/46) that nobody will be oppressed and therefore everybody will be treated justly regardless of their religion.
There are many verses regarding the issue. Two verses that address unbelievers directly are as follows:
“(Disdainfully) bending his side, in order to (lead men) astray from the Path of Allah; for him there is disgrace in this life, and on the Day of Judgment we shall make him taste the Penalty of burning (Fire). (It will be said): "This is because of the deeds which thy hands sent forth, for verily Allah is not unjust to His servants.”(Hajj, 9-10)
The following verse states that no deed, whether small or big, will be lost and that every deed will be rewarded or punished: “Then shall anyone who has done an atom's weight of good, see it! And anyone who has done an atom's weight of evil, shall see it.” (az-Zilzal, 99/7-8)
"Zarra" mentioned in the verses means a tiny ant or a particle that can be seen only in the sunlight. What is meant here is stating man's responsibility through the smallest thing that human senses can be interested in. The real aim is to state that the smallest good or bad deed will not be lost in the eye of Allah.