The phrase fi sabilillah (في سبيل الله fī sabīli llāhi) is an Arabic expression meaning "in the cause of Allah", or more befittingly, "for the sake of Allah". Alternative spellings for fi sabilillah include fisabilillah and fisabillillah and is defined as, "One who fights for the cause of Allah" or "Jihad in the way of Allah".
- إِنَّمَا الصَّدَقَاتُ لِلْفُقَرَاءِ وَالْمَسَاكِينِ وَالْعَامِلِينَ عَلَيْهَا وَالْمُؤَلَّفَةِ قُلُوبُهُمْ وَفِي الرِّقَابِ وَالْغَارِمِينَ وَفِي سَبِيلِ اللَّهِ وَاِبْنِ السَّبِيلِ فَرِيضَةً مِنَ اللَّهِ وَاللَّهُ عَلِيمٌ حَكِيمٌ
- "Alms are for the poor and the needy, and those employed to administer the (funds); for those whose hearts have been (recently) reconciled (to Truth); for those in bondage and in debt; in the cause of Allah; and for the wayfarer: (thus is it) ordained by Allah, and Allah is full of knowledge and wisdom." (trans. Abdullah Yusuf Ali)
From the above context it is closely associated with almsgiving or charity, as in جعله في سبيل الله, meaning "he dedicated the revenue or profit to be used in the cause of God", i.e. "he gave to charity". A classical example discussed by Lane in his Arabic-English Lexicon of 1863 is that of Umar who decided to give the revenue of a palm grove of his to charitable use. Because of these connotations, the phrase is closely associated with the concept of zakah in fiqh (Islamic jurisprudence). According to the classical Sharia law manual of Shafi'i, Reliance of the Traveller, Jihad means to war against non-Muslims, and is etymologically derived from the word mujahada signifying warfare to establish the religion  Such a "just war" or "war in the cause of God" has been propagated in modern Islamic fundamentalism beginning in the late 19th century, and notably in the mid-20th century in Islamic revivalism.
- Lane, p. 1301, s.v. سبل: "in the way meaning cause, of God, or religion; or in the doing of anything , or all, that God has commanded, or of the works whereby one pursues the way that leads to advancement in the favour of God "
- Rudolph Peters, Jihad in classical and modern Islam: a reader 2005, p. 107 and note p. 197.