In Islam, the mahr (dower) is a woman's right and that signifies a husband's love and appreciation for his wife. There is no fixed amount of mahr in the Shari`ah. It should be given according to the financial status of the husband and according to the time and place. However, it should be reasonable and not too expensive. There is no limit to the amount of dower. Dower is generally divided into two parts, termed mu'ajjal, "prompt," and mu'ajjal "deferred." The mu'ajjal portion is exigible [payable] on entering into the contract, while the mu'ajjal part of the dower is payable upon dissolution of the contract. Although the first part is payable, and is sometimes paid at the time the contract is entered into, it has been the general practice (at least in Bangladesh) to leave it unpaid, and so like an on-demand obligation, it remains due at all times; the wife's right to the same not being extinguished by lapse of time.
Under common law, the legal right of a wife or child to a part of a deceased husband's or father's estate, regardless of the provisions in his will. The dower has special significance. When a man and a woman pledge to marry, it is the man who takes the financial responsibility of the woman, he is bringing home. The dower is nothing but a symbolic expression of this responsibility. The Qur’an uses the words ‘صَدَقَه’ (S@adaqah) and ‘اَجَر’ (Ajar) for it. Both words imply money which is given to a wife for her needs in return for her companionship. Dower payment is an ancient practice that was in vogue in Arabia before the advent of the Prophet Muhammad (sws).
Dower is a sum of money receivable by the wife from the husband as a consideration for the marriage, whereas dowry is an extra-dower consideration payable by one party to the marriage to another on the plea of bringing equality in marriage. Taking or paying or abetting payment of dowry has been made punishable under section 3 and 4 of the Dowry Prohibition Act, 1980. ….. [Abdul Kadir vs. Salima (1886) 8 All 149]
The amount of dower is usually divided into two parts, one called “prompt” which is payable on demand, and the other called “deferred”, which is payable on dissolution of marriage by death or divorce. ‘Deferred dower does not become prompt merely because the wife demands it.’ ….. [Manihar Bibi vs. Rakha Singh, (1954) A Manipur 1]
Where no details about the mode of payment of dower are specified in the nikah nama, or the marriage contract, the entire amount of the dower shall be presumed to be payable on demand. ….. [Section 10 of the Muslim Family Laws Ordinance, 1961]