4 وَءَاتُوا۟ ٱلنِّسَآءَ صَدُقَـٰتِهِنَّ نِحْلَةً ۚ فَإِن طِبْنَ لَكُمْ عَن شَىْءٍ مِّنْهُ نَفْسًا فَكُلُوهُ هَنِيٓـًٔا مَّرِيٓـًٔا
[4] And give their dowries willingly to women (as an obligation), but if they, of their own accord ,remit a portion of the dowry, you may enjoy it with pleasure.7
7Hadrat `Umar and Qadi Shuraih have ruled that if a wife remits the whole of her dowry or a part of it but later on demands it, the husband shall be compelled to pay it because the very fact that she demands it is a clear proof that she did not remit it of her own free will. (For further details, consult my book Huquq-uz-Zaujain, under the caption Dowry)