Praise be to Allah.
If the state gives you money to take care of your children, as appears to be the case from what you have said, then the money belongs to you and you may spend whatever is surplus to your needs and those of your dependents on whatever you like. In fact, you must go for Hajj if you can afford the costs of Hajj in addition to what you spend on your needs and those of your dependents.
But if the state gives the money to the children, and makes you in charge of spending on them, then the money belongs to them. Can you take something from their money in order to do Hajj?
There is a difference of opinion among the fuqaha’ concerning that.
1.. The Hanbalis are of the view that the father may take whatever he wants from his son’s wealth whether there is a desperate need for it or not, so long as that is not detrimental to the son’s interests. Based on that, you may take some of your children’s money to do Hajj.
They quoted as evidence for that the hadith narrated by Ahmad (6678), Abu Dawood (3530) and Ibn Maajah (2292) from ‘Amr ibn Shu‘ayb, from his father, from his grandfather: A man came to the Prophet (blessings and peace of Allah be upon him) and said: O Messenger of Allah, I have wealth and children, and my father is in need of my wealth. He said: “You and your wealth belong to your father. Your children are among the best of your earnings, so you may take from your children’s earnings and make use of it and enjoy it.” There are other isnaads and corroborating reports which mean that it is saheeh. See: Fath al-Baari (5/211) and Nasab ar-Raayah (3/337).
2. The majority of scholars are of the view that it is only permissible for the father to take from his child’s wealth on condition that he is in need; in other words, that he is in need of food, drink, clothing and the like.
Based on that, he does not have the right to take money in order to do Hajj.
They quoted as evidence the general meaning of the texts which prohibit taking the wealth of someone else except with his willing consent, and the fact that permission to take from one’s child’s wealth is limited to cases of need.
It was narrated that ‘Aa’ishah (may Allah be pleased with her) said: The Messenger of Allah (blessings and peace of Allah be upon him) said: Your children are a gift from Allah to you. He bestows upon whomever He wills females and He bestows upon whomever He wills males, so they and their wealth belong to you, if you need it.
Narrated by al-Haakim (2/284) and al-Bayhaqi (7/480). The hadith was classed as saheeh by Shaykh al-Albaani in as-Silsilah as-Saheehah (2564).
Ibn Qudaamah (may Allah have mercy on him) said: The father may take whatever he wishes from his son’s wealth and take possession of it, whether the father needs what he takes or not, and whether the child is a minor or an adult, subject to two conditions:
Firstly, that he does not treat his son unfairly or cause harm to him, and he does not take anything that the son needs.
Secondly, that he does not take money from one son and give it to another. This was stated by Ahmad according to a report narrated by Ismaa‘eel ibn Sa‘eed. That is because it is prohibited to single out one of his children for gifts from his own wealth, so it is more appropriate that it should be forbidden to single out one of his children for a gift taken from the wealth of another child.
Abu Haneefah, Maalik and ash-Shaafa‘i said: it is not permissible for him to take anything from his son’s wealth except as much as he needs, because the Prophet (blessings and peace of Allah be upon him) said: “Indeed your blood and your wealth are sacred to you, as sacred as this day of yours in this month of yours.” Agreed upon. And because the son has complete ownership of his own wealth, so it is not permissible for the father to take it away from him, such as taking away something that the son needs." (Al-Mughni 6/320).
We have previously stated on our website that the favoured few is the view of the majority of scholars, and that the father does not have the right to take anything from his son’s wealth when he has no need for it.
See the answer to question no. 9594 .
And Allah knows best.