Sources of income for the bayt al-maal (treasury) in the Muslim state
Question

                If zakaah can only be spent on the eight categories mentioned in the verse, then how can the Muslim state raise what it needs of funds to pay its employees, and to build roads, hospitals, schools, universities and other things that the state is required to do?
Praise be to Allah.Firstly:
The causes on which zakaah may be spent are defined in the verse in which Allah, may He be exalted, says (interpretation of the meaning):
“Zakaah expenditures are only for the poor and for the needy and for those employed to collect [zakaah] and for bringing hearts together [for Islam] and for freeing captives [or slaves] and for those in debt and for the cause of Allah and for the [stranded] traveler - an obligation [imposed] by Allah . And Allah is Knowing and Wise”
[at-Tawbah 9:60].
For an explanation of this verse, please see the answer to question no. 46209.
Secondly:
With regard to the sources of income of the bayt al-maal (treasury), they are many and varied both in the past and in the modern era.
In al-Mawsoo‘ah al-Fiqhiyyah (8/245-248) it says:
Sources of income for the bayt al-maal:

Zakaah of all types, which the ruler takes whether it is taken from wealth that is visible or hidden, such as grazing livestock, crops, cash and trade goods.
One fifth (khums) of movable booty. Booty refers to all wealth that is taken from the disbelievers by means of fighting, apart from land and real estate. One fifth of this wealth is to be given to the bayt al-maal, to be spent on various prescribed causes. Allah, may He be exalted, says (interpretation of the meaning): “And know that anything you obtain of war booty - then indeed, for Allah is one fifth of it and for the Messenger and for [his] near relatives and the orphans, the needy, and the [stranded] traveller…” [al-Anfaal 8:41].
One fifth of metals and the like extracted from the ground, such as gold, silver, iron and so on. It was said that this also applies to what is extracted from the sea, such as pearls, ambergris and so on.
One fifth of buried treasure. This refers to all wealth that was buried underground by human actions. What is meant here is the treasure of the disbelieving people of the Jaahiliyyah (pre-Islamic period of ignorance). If a Muslim finds it, one fifth of it is to be given to the bayt al-maal; the remainder belongs to the finder.
Fay’, which is all movable wealth that is captured from the disbelievers without a fight and without mobilising troops. Fay’ is of different types:


Land and property from which the disbelievers fled for fear of the Muslims (at time of war). This is to be made into a waqf, like land that is seized by fighting, and its yield is to be shared out every year. This was stated by the Shaafa‘is, although there is a difference of scholarly opinion concerning the matter.
Movable wealth that is left behind and abandoned by the disbelievers. This is to be divided on the spot, and not turned into a waqf.
What is taken from the disbelievers of taxes or rental of land of which the Muslims have gained possession and rented out to a Muslim or a dhimmi [non-Muslim living under Muslim rule], or rental of land that the Muslims have left in the possession of its original owners, whether it was acquired on the basis of a peace deal or was taken by force then left in their hands on the grounds that they are still its owners and they pay kharaaj (land tax) to us.
Jizyah, which is a poll tax paid by the disbelievers in return for their living in Muslim lands. It is imposed on each adult, able-bodied male, or on a city as a whole, to pay a specific amount of money. If someone pays it who is not obliged to do so, it is regarded as a gift, not as jizyah.
One tenth paid by ahl adh-dhimmah [non-Muslims living under Muslim rule]. This is a tax paid on trade goods that they export to dar al-harb [hostile non-Muslim territory] or that they import from dar al-harb to dar al-islam [Muslim territory], or that they move from one city to another within Muslim territory. It is to be paid by them once a year.

Similar to that is the one tenth paid by traders from dar al-harb, if they come to us with trade goods and seek our protection.

What the non-Muslims in a state of war with the Muslims agree to pay in return for a peace deal.
The wealth of an apostate if he is executed or dies, and the wealth of a heretic if he is executed or dies. Their wealth is not to be inherited [by their heirs]; rather it comes under the heading of fay’. According to the Hanafis, the wealth of an apostate is subject to further discussion.
Wealth of a dhimmi [non-Muslim living under Muslim protection] who dies and has no heir, or what is left over from his wealth after his heirs have taken their shares.  This is also regarded as fay’.
Lands captured by means of fighting that are agricultural lands, according to those scholars who do not think that such lands are to be divided among the fighters who capture them.


The yield of land belonging to the bayt al-maal, or rent on property owned by the bayt al-maal, and earnings on related trade and business dealings.
Gifts, donations and bequests that are given to the bayt al-maal for jihad or other purposes that are in the public interest.
Gifts that are given to judges who were not given gifts before being appointed to that position, or gifts that are given to judges but the giver has a dispute before the judge. If these gifts are not returned to the giver, they are to be given to the bayt al-maal, because the Prophet (blessings and peace of Allah be upon him) took from Ibn al-Latbiyah [who was sent out to collect zakaah and gave the zakaah to the Prophet (blessings and peace of Allah be upon him) but he wanted to keep what was given to him as gifts] what had been given to him as gifts.

The same applies to gifts that are given to the ruler by non-Muslims who are hostile towards the Muslim state, and gifts that are given to state workers, unless the recipient pays towards these items from his personal wealth.

Taxes imposed on people in order to take care of their own interests, whether that is for jihad or other purposes. These taxes should not be imposed on them unless there are insufficient funds in the bayt al-maal to serve that interest and it is essential. Otherwise, this is an illegitimate source of income.
Lost wealth; this refers to wealth that is found but it is not possible to know who the owner is, whether it is found in the street, entrusted to someone for safe keeping, given as collateral, found with thieves and their ilk, and similar wealth of which no one claims ownership. It is to be given to the bayt al-maal.
The estate of any Muslim who dies and has no heir, or he has heirs who do not inherit all of his wealth, according to the scholars who think that what is left over should not be given to his relatives. In the case of someone who is killed and has no heir, the diyah (blood money) for his killing goes to the bayt al-maal and is to be spent on the same causes as the fay’.

The right of the bayt al-maal to this kind of wealth is subject to the rulings on inheritance, according to the Shaafa‘is and Maalikis. The Hanbalis and Hanafis say that it is to be given to the bayt al-maal according to the rules on fay’, not inheritance.

Penalties and confiscated wealth. It is narrated in the Sunnah that one who withholds zakaah is to be penalised by having half of his wealth seized. This is the view of Ishaaq ibn Raahawayh and Abu Bakr ‘Abd al-‘Azeez. It was narrated that a penalty is to be imposed on one who picks fruit for free and takes it out [of the garden or orchard]; the penalty is to be double the value of the fruit. This is the view of the Hanbalis and Ishaaq ibn Raahawayh. What appears to be the case is that when such penalties are taken, they are to be spent in the public interest, thus they become due to the bayt al-maal.

It was narrated that ‘Umar (may Allah be pleased with him) took half of the wealth of some people who were appointed to positions of authority when they became rich because of their positions.
One of the sources of income for the bayt al-maal in the modern era is the natural resources that were discovered in the lands of Muslim states, namely petroleum, natural gas, minerals and so on. It is very rare to find a state in which there are no resources of that nature.
Another source of income is what the state charges in return for what it carries out of agricultural, industrial or commercial projects, or services that it offers to the people, such as electricity, telephones, water and so on.
Thus it will become clear that there are many sources of income for the bayt al-maal.
And Allah knows best.