What are the laws of war, which have been framed by Holy Quran?

There are some certain bases of war that are peremptory; prior, during, and after. Islam is composed of serious body of rules. Every right confers upon its holder. In this regard, unbelievers, too, have some rights. As, Late Hamdi Yazir says, Right is a right, even it concerns an unbeliever Blasphemy of an unbeliever does not allow anyone to encroach upon his/her rights.

a. Bases prior to war

1. The principle that the treaties are binding
If an Islamic country had made a treaty with a non-Muslim country, it has to fulfill the agreement. With Quranic expression, fulfill the covenant: the covenant is surely subject to questioning (on the Day of Judgment you will be held accountable for your covenant). (Al-Isra Surah, 17:34)

In the verse that let Muslims declare a war on polytheists, it is stated as, Excepting those among the people who associate partners with God with whom you made a treaty, and who have not thereafter failed to fulfill their obligations towards you (required by the treaty), nor have backed anyone against you. Observe, then, your treaty with them until the end of the term (that you agreed with them). Surely God loves the God-revering, pious (who keep their duties to Him). (At-Taubah Surah, 9:4) How could there be a covenant with those who associate partners with God (and recognize no laws and treaty) on the part of God and His Messenger? – excepting those with whom you made a treaty in the vicinity of the Sacred Mosque: (as for the latter) so long as they remain true to you, be true to them. Surely God loves the God-revering, pious (who keep their duties to Him). (At-Taubah Surah, 9:7)

In accordance with the divine instructions, Muslims always abide the agreements; never transgress a treaty or an agreement. We believe in the benefit to convey the incident that had taken place in the Asr-i Saadah (Age of Happiness and Tranquility in which Prophet Muhammad lived). It has been on the authority of Huzayfa bin Al-Yaman who said, Nothing prevented me from being present at! The Battle of Badr except this incident. I came out with my father Husail (to participate in the Battle), but we were caught by the disbelievers of Quraish. They said: (Do) you intend to go to Muhammad? We said: We do not intend to go to him, but we wish to go (back) to Medina. Therefore, they took from us a covenant in the name of God that we would turn back to Medina and would not fight on the side of Muhammad (peace be upon him). So, we came to the Messenger of God (peace be upon him) and related the incident to him. He said: Both, of you proceed (to Medina); we will fulfill the covenant made with them and seek God's help against them.

Unbelievers have never seen any harm in not abiding the covenant. The Holy Quran explains the matter as, How (could there be a covenant with the others) when, if they were to prevail against you, they would observe towards you neither any bond, nor law, nor agreement, they seek to please you with their mouths but in their hearts they are averse; and most of them are transgressors (who habitually disregard all bounds of equity). (At-Taubah Surah, 9:8) That is to say, even if they win, they transgress a covenant. For instance, they say, No body will ever hurt, but never hesitate to massacre at the end. In fact, we see many examples of their wrongdoings throughout the history. Meccans to transgress the Hudaibia treaty,

Divine Decree about the ones who make a practice of transgressing covenants is as follows: Those of them with whom you have made a treaty, and who break their treaty on every occasion without fearing God. If you meet them in war, deal with them in such a manner as to deter those behind them (who follow them and those who will come after them), so that they may reflect and be mindful. (Al-Anfal Surah, 8:56, 57) Prophet Muhammad executed the decree of the Bani Qurayza Jews in accordance with the above given verse. (3)

This following verse is also about transgressors, But if they break their pledges after their treaty (with you) and assail your religion, then fight with those leaders of unbelief – surely they have no trustworthy pledges – so that they may desist (from aggression). (At-Taubah Surah, 9:12) The expression mentioned at the end of the verse, so that they may desist (from aggression) depicts that the intent of the war is not massacring, but to dissuade transgressors from their cruelty and injustice. (4)

Besides, there would be a risk of transgression of the counterparty. In such a case, thing to do is given in the following verse, If you have strong reason to fear treachery from a people (with whom you have a treaty), return it to them (i.e. publicly declare to them, before embarking on any action against them, that you have dissolved the treaty) so that both parties should be informed of its termination. Surely God does not love the treacherous. (Al-Anfal Surah, 8:58) As it is clearly understood from the verse, if the transgression of the counterparty is not obvious, but if there is a possibility of any treachery, they should be informed that the covenant is abrogated. It is not religiously permissible to attack all of a sudden. (5) Informing about the abrogation of the covenant would be a nobly behavior. Otherwise, counterparty would set up a howl.

2. Invite to accept Islam

Prophet Muhammads appointment of the commander in chiefs of expeditions and his advise to them on etiquettes of war and three courses of action that they should invite polytheists:

It has been reported from Suleiman b. Buraid through his father that when the Messenger of Allah (may peace be upon him) appointed anyone as leader of an army or detachment he would especially exhort him to fear Allah and to be good to the Muslims who were with him. He would say: Fight in the name of Allah and in the way of Allah. Fight against those who disbelieve in Allah. Make a holy war, do not embezzle the spoils; do not break your pledge; and do not mutilate (the dead) bodies; do not kill the children. When you meet your enemies who are polytheists, invite them to three courses of action. If they respond to any one of these, you also accept it and withhold yourself from doing them any harm. 1. Invite them to (accept) Islam; if they respond to you, accept it from them and desist from fighting against them. Then invite them to migrate from their lands to the land of Muhajirs and inform them that, if they do so, they shall have all the privileges and obligations of the Muhajirs. If they refuse to migrate, tell them that they will have the status of Bedouin Muslims and will be subjected to the Commands of Allah like other Muslims, but they will not get any share from the spoils of war or Fai' except when they actually fight with the Muslims (against the disbelievers). 2. If they refuse to accept Islam, demand from them the Jizya. If they agree to pay, accept it from them and hold off your hands. 3. If they refuse to pay the tax, seek Allah's help and fight them. When you lay siege to a fort and the besieged appeal to you for protection in the name of Allah and His Prophet, do not accord to them the guarantee of Allah and His Prophet, but accord to them your own guarantee and the guarantee of your companions for it is a lesser sin that the security given by you or your companions be disregarded than that the security granted in the name of Allah and His Prophet be violated When you besiege a fort and the besieged want you to let them out in accordance with Allah's Command, do not let them come out in accordance with His Command, but do so at your (own) command, for you do not know whether or not you will be able to carry out Allah's behest with regard to them. (Sahih Muslim, Book 019, Number 4294) As it is seen, war proposed as a final solution. These three courses of action should not be applied under every circumstance. Hudaibia Treaty is a fine example to that. (8)

b. During War

War is chaos. It is a place for killing and dying. Anyone can lose his continence. Common sense is left destitute, feelings loom large. The following verse teaches us how to react in those kinds of situations.

Fight in Gods cause (in order to exalt His Name) against those who fight against you, but do not exceed the bounds (set by God), for surely God loves not those who exceed the bounds. (Al-Baqarah Surah, 2:190) Fight against those who fight against you gives the message of not fighting against elders, children, women, and clerics. (9) However, if women are fighting against you, it can be fight against them. (10)

Do not exceed the bounds expression, on the other hand, forbids such exorbitances as cutting noses or ears.

One other situation in a war is the situation of the people who crave for mercy, O you who believe! When you go forth (to war) in Gods cause, investigate with care until the situation becomes fully clear to you, and do not say to anyone who offers you (the greeting of) peace (thereby indicating his being a Muslim), "You are not a believer," seeking the fleeting gains of the present, worldly life; for with God are gains abundant. Even thus (as he now is) were you before (ignorant of faith and what being a Muslim is, and you too entered Islam with a similar word); but God has since then been gracious to you. So investigate with care until the situation becomes fully clear to you. Surely God is fully aware of all that you do. (An-Nisa Surah, 4:94)

Sources:
1-Yazır II, 1451
2-Müslim, Cihad, 98
3-Beydavi, II, 224; İbnu Kesir, VI,397-398; İbnu Hişam, III, 249-251
4-Yazır, IV, 2468
5-Azzam, s. 161
6-Kutub, III, 1542
7-Müslim, Cihad, 3; Tirmizi, Siyer, 48; İbnu Mace, Cihad, 38
8-Azzam, s.151
9-Beydavi, I, 108
10-Sabuni, Revaiu'l-Beyan, I, 217
11-İbnu Kesir, I, 328; Beydavi, I, 108; Sabuni, Revaiu'l-Beyan, I, 216-217