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 is His slave and Messenger.
Imaams Ahmad and Ibn Maajah reported on the authority of 'Abdullaah Ibn 'Umar and his father, that a man came to the Prophet to present a dispute between him and his father and said, "O Messenger of Allaah, he is in need of my money," and the Prophet said to him: "You and your property belong to your father."
Here, "belong to your father," means that using the money of a child is lawful for the father. It does not mean that the ownership of all the belongings of a child is transferred to his father because the child is responsible to pay the Zakah (obligatory charity) of his property, and his property is also to be distributed among his heirs after his death. Thus, the Prophetic narration approves of a father taking and using the money of his child as long as he does not spend it lavishly and whether his child permits him or not.
The Muslim jurists have clearly stated that a father can freely use the money of his child subject to two conditions, as mentioned by Imaam Ibn Qudaamah :
First, he should not do wrong to his son, should not harm him, and should not use the thing that the child is in need of.
Second, he should not take from a child to give to another child. Imaam Ahmad mentioned this point specifically.
Imaam Ibn Qudaamah added, "Imaams Maalik, Abu Haneefah, and Ash-Shaafi'ee said, that he (a father) has no right to take from the belongings of his son except according to his need." The Prophet said: "Indeed your blood and your property are as sacred and inviolable as the sacredness of this day of yours, in this month of yours, in this town of yours…"
The opinion of scholars that a father can take only what he needs is based on the narration that the Prophet said: "They (your children) and their properties belong to you, if you need them." [Al-Haakim and Al-Bayhaqi]
Therefore, the aforementioned saying of the Prophet "You and your property belong to your father," should be understood as we explained. So, a father should not cause harm to his son taking from him what he wishes based on his misunderstanding of the narration. Also, know that the narration includes female children as well, as the narration reported by Al-Haakim reads: "Your children are your gift…… they and their properties belong to you."
Allaah Knows best.