The possibility of error resulting in a fight within the believers cannot be ruled out. It does not, however, befit a believer to kill another believer. Whether it is done out of egoism or cupidity, to acquire wealth or land it is highly unbecoming of a believer to kill another believer, whether at individual or national level. A Muslim is not allowed to fight with another Muslim, nor can two Muslim be made to light, but if by mistake a Muslim does kill another then he is bound to do two things. Firstly, he must set free a believing slave since the term here is "Raqaba-tim-Mu'minaly'.
Secondly, he must pay the blood money to the family of the victim as settled; but if they forgo it then it is all right not to pay. In those days the legal rate of blood money was fixed at one hundred camels or one thousand dirhams. Muslim jurists have deliberated on the forms of premeditated murder and murder by mistake, and have discussed at length the relevant blood money, which can be found in Books on Fiqh. Here we do not aim at going into details but to describe it only in commonly understandable words. If amongst the relatives of the deceased if some forgo their shares of blood money, the rest must be paid. If all the relatives forgo their shares only then all will be forgiven.
In another situation, where the deceased's tribe have a peace pact with the Muslims, the blood money is to be paid to his family and a believing slave must be set free as the Holy Prophet"-SW enforced an equal amount of blood money both for believers and for the non-believing subjects under the Muslim rule. If one is unable to compensate in the above-mentioned way, he must fast for two months in continuity and must repent and beg for forgiveness in order to cleanse his heart of the darkness of sin. Since the continuity too has been ordered in the Quran, he must last for two months without a break. If he misses a fast due to any reason, he shall start all over again and will complete the two month count. However, for a woman, the continuity will not be affected by the fasts missed in her menstrual days. After collecting evidence from the Ahadith, and after painstaking discussions and reasoning, the Muslim jurists have declared that the blood money of a woman is half to that of a man. Nowadays this issue is attracting vehement criticism and liberal or progressive scholars consider it a sign of wisdom to oppose it in writing and speech. In my humble opinion we have no right to raise any objection on an issue which has been endorsed by the sayings of the Holy Prophet'-SW as the explanation and implementation of Quranic Ayat and injunctions is the office of the Holy Prophet-SW alone. Still if someone is adamant on objecting, it is the same as arguing why woman was made a woman!
If a person does not even have the strength to fast, he should repent sincerely and should resolve that as soon as health is restored he shall start fasting. Then as soon he feels up to it, he should do so, as Allah-SWT knows the truth and the inner secrets, and is the Wisest. This Wisdom is manifested in all His-SWT creations and all of His-SWT Commandments. In yet another situation where someone murders a believer premeditatedly as mentioned before, either for satisfying the ego, or for greed or for gaining power, then the killer shall be condemned to Hell forever, from which there is no escape. Not only this, but also he will be accursed by Allah-SWT and qualify for His-SWT Wrath. An excruciating retribution has been prepared for such sinners, but if they sincerely repent and beg Allah's Forgiveness and employ the means to atone as prescribed in the Islamic code, Allah-SWT is extremely Gracious. The contemporary Muslim rulers let millions of innocent Muslims put to death for the sake of their short-lived reign. Then victims do not even know why they are being killed. It is a wonder, what justification will the rulers and Governments give for their actions on the Final Day? Murder of a believer in cold blood leads to eternal condemnation to Hell, a punishment that does not coincide with faith, as a believer shall not be doomed to Hell forever. The Commentators have written elaborate and interesting explanations in this regard. What I have understood is that a believer who murders another believer and has repented, since he was guilty of trespassing the victims' as well as Allah-SWT's right, it is possible that Allah-SWT may forgo His-SWT own right, and leave the matter to the aggrieved. It is also possible that Allah-SWT obtains a pardon for the repentant from the victim by generously rewarding the latter, or creates any other such situation for the salvation of the former. And if punishment is awarded, a believer will not abide in Hell forever because of faith. The real danger is that such a criminal will lose faith before he dies. Intentional killing of a believer is such a grave sin that it brings the killer closer to disbelief. If he does not repent, it is certain that he will not die as a believer.
Lastly it is recommended that whenever Muslims go on a campaign in the Cause of Allah-SWT or for Jihad they must always thoroughly investigate the situation. Islam has laid great emphasis on two issues. Firstly, discipline in all expeditions whether great or small; on a journey or Jihad, there will always be one leader and the rest of the group will obey him. Secondly, investigation of facts, so that no action should be taken on mere conjectures. Rather, inquiries must be made to get to the crux of the matter. If someone declares himself to be a Muslim before the Muslim army, it must not be said that he is not a believer and is only claiming faith in order to save his life. Such incidents did occur, and are quoted as the context of the revelation of these Ayat. The claim of such a person must also not be rejected in order to deny him booty or merely for any other worldly gain. Allah-SWT has immense treasures in store for Muslims. In due time, the possessions of mighty kingdoms would be distributed in the streets of this very city. Hence there is nothing to worry.
Allah-SWT , therefore, advises Muslims not to lose patience or be lured by petty gains as they are to fight only for Allah-SWT's Pleasure. So, they must accept whoever declares to be a Muslim. Allah-SWT reminds the believers that they too were in a similar state once. It is only for Allah-SWT's Grace and His-SWT great favour that He-SWT raised His-SWT exalted Prophet'-SW and changed their destiny: otherwise had they been any different. Thus the Muslims should investigate before accepting or rejecting someone's declaration of Islam. From here the Jurists have deduced that a Muslim should not be charged with infidelity, no matter how sinful he may be. But a person will qualify to be called a Muslim only when his verbal declaration of Islam is complemented by his belief in all the requisite tenets essential for faith. If someone recites Kalimah-e-Tayyibah but prostates before an idol, or adopts the ways of infidels such as wearing cross threads or a bracelet, or else denies any tenet of Islam such as the Day of Judgement, Barzakh. Angels, Heaven or Hell, he shall not be considered a Muslim. Therefore, it is recommended to thoroughly check out the credibility of a claimant and whatever one does is in the knowledge of Allah-SWT . He-SWT knows that there are certain Muslims who abstain from going out on Jihad without any reason. But bear in mind that those who sit back can never be equal to those who lay down their lives and sacrifice their wealth in the Cause of Allah-SWT .
Here, a question about Tasawwuf is also answered. There are some people who work hard and spend money to convey Allah-SWT ’s Message to people, whereas others sit back and wait for someone to take them to the venue of Allah-SWT ’s Zikr. Allah-SWT asks whether those who sit back can ever be equal to those who strive in Allah-SWT ’s Way with their time, wealth and life? Never! In fact Mujahidin are always blessed with status higher than of those who cannot work very hard. Yet it is true that Allah-SWT promises His-SWT Mercy, Grace and Endearments to all. A point to be understood from this is that if a group of people are involved in Jihad and there is no need for more to join in, then it will be a Fardh Kifayah and the rest of the Muslims would be absolved of the obligation. This is normally the rule for all communal affairs such as the funeral, the imparting of religious education and the propagation of religion. If a group of people from the community perform these duties, the rest are absolved. But those who actively participate in these shall attain excellence. People striving in Allah-SWT ’s Cause will by far excel in ranks over those who do not. Although all believers shall receive their share of Allah-SWT ’s bestowal, Mercy and bounties, but those who work hard will enjoy much superior status than the others. This is only until Jihad remains Fardh Kifayah. If the task goes beyond those engaged in it, it will become incumbent upon those who are geographically the nearest. If it exceeds even them, the next nearest believers will be obligated, and so on. So much so that Jihad can become an obligation on the entire Muslim world at the same time, as the orders referring to it vary with the circumstances. Human weaknesses aside, man must work with sincerity, and then Allah-SWT ’s Grace and Mercy enshrouds human errors. But it is imperative that one acts out of devotion and with all one's heart. That granted, Allah-SWT is extremely generous and forgiving.