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, “doing anything for the sake of God and in the way of God to gain nearness to Him and gain His pleasure.” 
- 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).
- 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 "