This is straight out of the Qur’an, which has an entire chapter entitled “Booty” (Spoils of War) — chapter eight. That chapter stipulates that Muhammad always gets a cut — twenty percent: “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] traveler, if you have believed in Allah and in that which We sent down to Our Servant on the day of criterion – the day when the two armies met. And Allah, over all things, is competent.” (8:41) Nowadays, that would be the emir’s, as Mizanur Rahman notes here that “the booty must be gathered and given to the emir, even if you dislike how it is spent.”
“British Jihadi Cleric Abu Baraa to Syrian Rebels: You Should Rely on Booty, Not American Aid,” from MEMRI, n.d.:
Following are excerpts from a video by British Jihadi cleric Mizanur Rahman a.k.a. “Abu Baraa”, which was posted on the Internet on October 22, 2013:
Abu Baraa: Allah has warned us of many temptations. He warned us of obstacles in the path of Allah. He warned us about our enemies, near and far, including our own enemies within ourselves. The Jihad is not always fought against the enemy with our hands, but you have your own enemy from Satan, from your own soul.
This is why the first preparation for Jihad for the sake of Allah, and especially for those already in the battlefield in Syria… You must always be constant in your own ihtisab — holding yourself to account and checking yourself in your own sincerity, your own intentions, and loyalty, because there are certain things which will destroy the Jihad, and will remove the possibility of victory — which is only in the hands of Allah. Allah will take away the victory from you, because of your insincerity.
The other lesson that we learn from Andalusia is allegiance and disavowal. The governors in Andalusia started to forget about their allegiance only to Islam, and started to seek the help of the Christian neighboring kings against their own Muslim brothers, the governors in Andalusia. Again, the Christian kings took advantage of this infighting between the Muslims, siding with one against the other, until they destroyed all of the Muslim governments, and they took control back again in Andalusia. That is how the Muslim world was destroyed in Andalusia, and that is how the Americans seek to destroy you now in Syria.
They want to side with one side of the army against Bashar Al-Assad against the other, and they want to promote their own ideas, until they can destroy and remove both sides of the Muslim armies and mujahideen, in order to plant their new puppet and their own interest in the region again. That is the plot of Satan and the plot of America, just as it was the plot of the Christian kings in Andalusia. Don’t fall for the same mistake.
One of the ways that the Americans wish to do this is by money — the temptation of money — because the Jihad cannot function without money. So when the disbelievers start to offer you money, or the hypocrites offer you money, or the people of apostasy offer you wealth, booty, and resources to fight Jihad — they are placing conditions and restrictions upon that.
So my dear brothers, don’t bother looking to the West or the East, or to the infidels, the apostates, or the hypocrites for your support, your wealth, or to fund your struggle against Bashar Al-Assad. Be independent. The best source of resources for Jihad is to take it from the enemy. This is why booty is known as the best source of income.
If you, at that moment in battle, were concerned about the booty, and you went after the enemy for the sake of his booty and wealth, for the sake of his gun, his horse, his camel, or his car, and you died in that state, at that moment an arrow or a bullet were to hit you — you would die with the intention of fighting for an animal — what is known as Shahid Al-Dab — the martyr of the animal.
The booty must be gathered and given to the emir, even if you dislike how it is spent.
My dear Muslim brothers, don’t bother about what happens to the money. Don’t look at who is spending and who is receiving it. Don’t look at who is given the money or the booty. It is not for you. It is for Allah and His Messenger. It is for Jihad for the sake of Allah. Maybe the reward you will receive in the Hereafter is much greater than any reward in this world.