HOLY WAR is to expend oneself in the way of God and to honor His Word which He has laid down as a path to Paradise and a highway leading thereto. Said He: "Do valiantly in the cause of God as it behooveth you to do for Him."
It is a duty, incumbent on the community of the believers collectively, to be carried out by some on behalf of the whole community. God said: "The faithful must not march forth all together to wars; and if a part of every band of them march not out, it is that they may instruct themselves in their religion." In other words, God has enjoined that some should march to battle for His cause, while others stay behind to keep the torch of His law burning. Said God again: "Those believers who sit at home free from trouble, and those who do valiantly in the cause of God with their substance and their persons, shall not be treated alike. God hath assigned to those who contend earnestly with their persons and with their substance a rank above that of those who sit at home. Goodly promises hath He made to all. But God hath assigned the strenuous a rich recompense, above that of those who sit at home: rank of His own bestowal, and forgiveness, and mercy; for God is Indulgent, Merciful." Furthermore, the Prophet embarked upon his wars and raids with but a few of his followers; he left some behind at home.
Others have maintained that Holy War was a duty obligatory upon every Moslem individually. In support of their position they cited the words of God when He said: "Attack those who associate other gods with God in all, as they attack you in all." And again: "March ye forth the light and heavy armed, and contend with your substance and your persons in the Way of God. This, if ye know it, will be better for you." And still again : "War has been prescribed to you, but from it ye are averse."
At any rate, Holy War is among the best forms of worship and one of the most acceptable works of righteousness before God. Thus He said: "Verily God loveth those who, as though they were a solid wall, do battle for His cause in serried array. O ye who believe! Shall I show you a merchandise that shall deliver you from the sore torment ? Believe in God and in His Apostle, and do valiantly in the cause of God with your wealth and your persons. This, did ye but know it, will be best for you. Your sins He will forgive you, and He will bring you into gardens beneath the shades of which rivers flow; into charming abodes in the gardens of Eden. This shall be the great bliss." God also said: "And repute not those slain in the path of God to be dead. Nay, alive with their Lord, are they richly sustained; rejoicing in what God of His bounty hath vouchsafed them; filled with joy for those who follow them, but have not overtaken them, that on them nor fear shall come, nor grief; filled with joy at the favors of God, and at His bounty, and that God suffereth not the reward of the faithful to perish." He also said: "Verily, of the faithful God hath bought their persons and their substance, on condition of Paradise for them in return; on the path of God shall they fight, and slay, and be slain. A promise for this is pledged in the Evangel, and in the Koran, and who is more faithful to his engagement than God? Rejoice, therefore, in the contract that ye have contracted; for this shall be the great bliss."
The Apostle of God, on being asked concerning the best acts of worship, replied: "Belief in God and Holy War in the cause of God." He also said: "Compared to Holy War, all the acts of worship put together are like a drop of water in the spacious sea." And again: "If I should spend the whole night in prayer and fast the entire day, I would not attain the stature of him who spends a day in Holy War." And again: "He who dies without having taken any part in Holy War, or without ever entertaining such an undertaking in his mind, is guilty of deceit and hypocrisy."