The mahr (dowry) is the right of the woman and it is an obligation upon her husband. So, the basic ruling is to give the wife her dowry in full, abiding by Allah’s Command in the verse, “And give unto the women, (whom ye marry) free gift of their marriage portions” (An-Nisaa’: 4).
Thus, it is impermissible for the husband, or any other person like her father or her brother, to take anything from the wife’s dowry except with her consent, as Allah Almighty says, “but if they of their own accord remit unto you a part thereof, then ye are welcome to absorb it (in your wealth)” (An-Nisaa’: 4).
Dr. Husam al-Din Ibn Musa `Afana, professor of the Principles of Islamic Jurisprudence at Al-Quds Univ., Palestine, states: Dowry is the woman’s exclusive right, so nothing should be taken from it except with her consent, which must be clear and explicit without any coercion, shyness or the like. Therefore, it is impermissible to take from the wife’s dowry, whether as money or gold, except if she totally agrees. The Messenger of Allah (peace and blessings be upon him) said, “The property of a Muslim is not lawful to be taken except of his own accord” (Reported by Ahmad, Al-Bayhaqi, Ad-Daraqutni and others).
Since the dowry is the wife’s exclusive right, she is entitled to dispose of it in any way she likes. She can exempt her husband from all or some of it, or she can give all or some of it to him. However, all this should be done from her own free will and choice.
The righteous wife is the one who feels what her husband feels and stands by him in times of hardship and calamity. If she gives him some of her dowry as a gift or a loan, she will receive a great reward from Almighty Allah and appreciation and respect from her husband.