WaAAlamoo annama ghanimtum min shay-in faanna lillahi khumusahu walirrasooli walithee alqurba walyatama (surah Anfal: 41)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(8:41) Know that one fifth of the spoils that you obtain belongs to Allah, to the Messenger, to the near of kin, to the orphans, and the needy, and the wayfarer. *32 This you must observe if you truly believe In Allah and in what We sent down on Our servant *33 on the day when the true was distinguished from the false, the day on which the two armies met in battle. Allah has power over all things.

Wa`lamooo annamaa ghanimtum min sha`in fa anna lillaahi khumusahoo wa lir Rasooli wa lizil qurba walyataamaa walmasaakeeni wabnis sabeeli in kuntum aamantum billaahi wa maaa anzalnaa `ala `abdinaa yawmal Furqaani yawmaltaqal jam`aan; wal laahu `alaa kulli shai`in Qadeer

*32). This verse lay's down the law for distributing the spoils of war. Spoils of war, as mentioned earlier, essentially belong to God and His Messenger. They alone have the right to dispose of them. As for the soldiers who fight, they are not the rightful owners of the spoils; whatever they do receive should be considered an extra reward from God rather than their legitimate right.
Here it is stated how God and His Messenger decided to dispose of the spoils. The prescribed rule is that the soldiers should depbsit all the spoils with the ruler or the commander without making any effort to conceal anything. One-fifth of the spoils thus deposited would be assigned for the purposes mentioned in the present verse and four-fifths would be distributed among the soldiers who had taken part in the fighting. In keeping with the directive contained in the present verse, after every battle the Prophet (peace be on him) used to proclaim: 'These are your spoils. My own share in them is no more than one-fifth and even that fifth is spent on you. Bring everything, even if it be a piece of thread or a needle, or anything bigger or smaller, and take nothing by stealth (gulal), for taking by stealth is a shameful deed, and would lead to Hell.' (Ahmad b. Hanbal, Musnad, vol. 5, p. 316 - Ed.)
It is pertinent to remember that the share of God and His Messenger (peace be on him) in the spoils signifies that a part of the spoils should be earmarked for the struggle to exalt the Word of God and to establish Islam as an operational system of life..
As to the word 'kinsmen' in the verse, during the Prophet's lifetime, it stood for his relatives. Since the Prophet (peace be on him) devoted all his time to the cause of Islam, he was not in a position to earn his own living. Hence, some arrangement had to be made for the maintenance of the Prophet (peace be on him) as well as for his family, and the relatives dependent upon him for financial support. Hence a part of khums (one-fifth of the spoils of war) was specified for that purpose. There is, however, some disagreement among jurists as to whom this share should go to after the Prophet's death. Some jurists are of the view that after the Prophet's death the rule stands repealed. According to other jurists, this part should go to relatives of those who succeeded him to Caliphate. Other jurists are of the view that this share should be distributed among the poor members of the Prophet's family. To the best of my knowledge, the Rightly-Guided Caliphs followed the last practice. (See the comments of Qurtubi, Ibn Kathir and Jassas on the verse. See also Ibn Rushd, Bidayat al-Mujtahid, vol. 1, pp. 377-8 - Ed. )
*33). This refers to the support and help from God which brought about victory for the Muslims.