Is it permissible for the husband to waive the remaining agreed-upon Mahr (dowry) with his wife upon divorcing her, based on their prior agreement for her to relinquish her rights to 'iddah (post-divorce waiting period) and mut'ah (compensatory gift) expenses, in the event of her failure to come to him and her breaking promises, in addition to her not performing prayer?

If the husband has consummated the marriage with his wife, she is entitled to her full mahr (dowry), and he has no right to withhold any part of it from her upon divorce, as Allah (the Most High) says: {And if you want to replace a wife in place of another and you have given one of them a [large] amount [of gold], do not take [back] from it anything. Would you take it in injustice and manifest sin?}

The agreement between the spouses to pay the mahr in installments, to be received in payments each time the wife comes to her husband, is not binding, because it is a deferment of the mahr for an unknown term. The preponderant opinion in this case is that the deferment is void and the mahr becomes immediately due.

If the wife requests it, the husband must pay the remaining agreed-upon mahr, unless the wife willingly waives a part of it.

If the wife refuses to come to her husband without a valid excuse, she is considered nashiz (recalcitrant), and the husband may pressure her until she seeks khul' (divorce at her initiation by returning the dowry).

The husband's condition for the wife to waive the maintenance during the iddah (waiting period) and the mut'ah (compensatory gift) upon divorce is not binding, because it entails waiving a right whose cause of obligation has not yet arisen.

The husband is advised to communicate with his wife and strive to reconcile with her, especially regarding the observance of prayer. If the wife does not respond and does not maintain prayer, there is no good in her.

It is recommended to register the marriage in courts due to its significant benefits.