The Quran presents verses that talk about the division of war spoils and charity that goes to him and from which Muhammad decides what to do with it. Take Quran 8:41 and concept of Khumus. After the battle is over, the fighters would bring all the spoils to Muhammad. Then one-fifth is set apart to Allah and Muhammad, and the remaining four-fifths divided among those who took part in the fighting.This share is called “khumus” or one fifth. That is why Muhammad used to announce after every fight, “These spoils belong to you, and I have no share in these for my own person except the “Khumus” which is spent for your common good. Therefore bring here everything-even a needle and its thread. Do not hide anything, big or small, for this is a shameful thing and leads to Hell” .
It is all good until you read in one of the the Hadith what they mean by the “Khumus”:
The Prophet (ﷺ) sent Ali to Khalid to bring the Khumus (of the booty) and I hated Ali, and Ali had taken a bath (after a sexual act with a slave-girl from the Khumus). I said to Khalid, “Don’t you see this (i.e. What Ali did)?” When we reached the Prophet (ﷺ) I mentioned that to him. He said, “O Buraida! Do you hate Ali?” I said, “Yes.” He said, “Do you hate him, for he deserves more than that from the Khumus.”
Sahih al-Bukhari » Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi) » Hadith
Sahih al-Bukhari 4350
Source of Hadith: https://sunnah.com/bukhari/64/377
And in case you did not know Saffiya, one of Muhammad’s wives, was also a war bounty taken the form of Khumus after the genocide of Banu Nadir. She was the wife to be of the chief of the Jewish tribe. Muhammad went to pick up his Khumus and was told she was stunning looking, so he asked to see her. He saw how beautiful she is, so took her as his share! On the way back, he could not wait to reach his destination, he decided she was too attractive to risk anyone taking her, Muhammad rushed married her and nailed her that night!
The long story is here: https://sunnah.com/nasai/26/185
Source of Quran verse:https://quran.com/8/41
Source of Tafseer: https://www.alim.org/quran/tafsir/maududi/surah/8/41/
Can you feel the peace!?
They will claim that Muhammad never benefited financially from Islam, but that is not true. He did not have a job after the Dawah. Yet he had 9 wives and many slaves to feed. When he died he had a considerable wealth, that is why Fatima (his only daughter) had asked for her share but Abu Bakr decided (politically or otherwise) decided to donate it all.