Fee sabil lillah means for the sake of Allah–that is, making use of knowledge and deeds to attain Allah’s pleasure. Most scholars understood this phrase as fighting for the cause of Allah. Part of zakah designated for the cause of Allah is given to volunteer fighters, especially those who are not on the payroll of the state, regardless of their financial status.
The hadith of the Messenger of Allah, stated elsewhere, also confirms it: “Sadaqah is not permitted to the rich except to the following five: the warrior (ghuzi) for the cause of Allah… and so on.”
As to the pilgrimage (hajj, it does not fall under the zakah designated for the cause of Allah because it is an obligation for one who can afford it. Commenting on the issue, the authors of al-Manar say: “Spending of this portion on securing the routes of the pilgrimage and for providing water, food, and health services for the pilgrims is permissible if funds from other sources are not available.”
Included in the share designated “for the cause of Allah” are those spending in the interest of the common good that pertain to both religious and secular matters. The foremost is the preparations for war, including buying arms, food supplies for soldiers, means of transportation, and equipment for warriors. However, the supplies for warriors are to be returned to the treasury after the war. This applies especially to inconsumable items such as weapons, horses, and so on. A warrior does not always possess such items, for he uses them in the cause of Allah only when necessary. This is not the case, however, with other recipients of zakah, such as zakah collectors, debtors, people who received money under the expense account “reconciliation of hearts,” and the wayfarers. They do not have to return the zakah, even if they are no longer entitled to it.
Also included in the expense account “for the cause of Allah” are projects such as establishing military hospitals, paved and unpaved roads, the extension of military (not commercial) railway lines, and the building of cruisers, warplanes, fortresses, and trenches. An important item in this category could be the preparation of Muslim missionaries and sending them to non-Muslim countries to spread Islam, just as non-Muslim missionaries are now spreading their religions in Islamic countries. Also falling under this heading would be school expenses to prepare adequate courses in religious sciences and in other areas of public interest. Teachers involved in such programs should be given sadaqah as long as they continue to perform their assigned jobs without resorting to other means of income. Scholars who are rich should not be paid for their work, despite their obvious benefits to the people.