Sheikh what is the islamic ruling on the one who takes back waqf he gave

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

If you mean that a person made an endowment and then withdrew it and took it back, then if the endowment took place with its Islamically reliable conditions, then it becomes a binding contract and the endower does not have the right to withdraw it.

You did not mention to us, dear brother, whether the endowment has been taken possession of (by the party he endowed it to) or not? Because the scholars differed about the endowment when it is binding and irreversible? Some of them said that it is binding by statement, and others said that it is not binding except by taking possession of it.

Sharh Al-Muqni’ reads:

“Waqf (endowment) is a binding contract, it is not permissible to rescind it; it is binding just by saying it, because it is a donation that prevents sale, a gift, or an inheritance, so it is binding just by saying it, like emancipation (freeing a slave.)” [End of quote]

Sharh Al-Muqni’ also reads: “It is not binding except by taking possession of it, and letting the endowment off one’s hand – this is the view chosen by Ibn Abu Moosa, just like a gift. The first view is the correct one, and we have already stated it. Abu Haneefah held that the endowment does not become binding by statement only, and the one who endowed it may take it back unless he made a will about it for after his death, in which case, it becomes binding, or that a ruler rules that it is binding. Some of them narrated it on the authority of ‘Ali, Ibn Mas’ood, and Ibn ‘Abbas . But Abu Haneefah disagreed with his two companions, as their view is like that of all other scholars.” [End of quote]

Allah knows best.