what is the concept of Bait-ul Mall in islam

what is the concept of Bait-ul Mall in islam
assalamu aalaikum my question that .? what is the concept of Bait-ul Mall in islam from where it is generated?
Fatwa
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The Muslim Baitul-Maal (state treasury) is the place which is designed for keeping the spoils of war, charity, land tax and Jizyah (the tax which a free non-Muslim pays in Muslim countries in return for his protection), and this money should be in the hands of the caliph or a Muslim ruler who spends it in what Allaah has ordained.
However, a scientific study prepared in Kuwait university and which was published by the Scientific Committee in this university clarified that the establishment of Baitul-Maal started during the time of the Prophet, sallallaahu 'alayhi wa sallam, after Hijrah (i.e. migration from Makkah to Madeenah), and the statement that it did not exist until the caliphate of ‘Umar, may Allaah be pleased with him, is not correct.
The Prophet, sallallaahu 'alayhi wa sallam, used to have trustworthy people who kept these assets and they divided them with his order on those who deserved them. The mosque was the place in which the assets and belongings were exposed and the Prophet, sallallaahu 'alayhi wa sallam, would divide them by himself. However, the camels and other cattle remained in the folds until it was time for their division.
The same thing happened during the caliphate of Abu Bakr, may Allaah be pleased with him, and the beginning of the caliphate of ‘Umar, may Allaah be pleased with him.
When the conquests expanded and the wealth increased, departments were used, among which was the department of the treasury, and places for keeping the assets were created, and the money which is spent or received was recorded.
Allah knows best.