Regarding leaving the dowry unspecified: if consummation takes place, the author says:

“She is entitled to the customary dowry by virtue of the contract.”

Thus, that leaving of the dowry unspecified serves no purpose. A man consummates the marriage with his wife after leaving the dowry unspecified; then, the following morning, he brings the customary dowry. The woman’s guardians say, “You said that the dowry would be whatever the wife wants, and she wants a house, a car, and a servant.” He replies, “She is entitled only to the customary dowry. If she wanted these things, why did you not stipulate them at the time of the contract?”

The reason we revert to the customary dowry is that this designation is invalid, due to the deeply entrenched uncertainty involved. For if we say, “Whatever she wants,” what exactly does she want in terms of amount, category, and type? It is extremely vague, and something this vague is of no consequence. Therefore, we revert to the customary dowry.

“She is entitled to the customary dowry by virtue of the contract, and the judge determines it according to its proper amount. If the two reach an agreement before that, it is valid.”

His statement, “She is entitled to the customary dowry by virtue of the contract,” applies to both forms of leaving matters unspecified. In the case where the marital rights are left unspecified, she is entitled to the customary dowry upon consummation, and to a consolatory gift if she is divorced before consummation, by the explicit text of the Quran. In the case where the dowry is left unspecified, she is entitled to the customary dowry if she is divorced after consummation, because the rule is that when the stipulated dowry is invalid, she is entitled to the customary dowry. Here, the stipulated dowry is invalid because it is unknown.

If he divorces her before consummation, the authoritative school holds that she is entitled to a consolatory gift, because an invalid designation is equivalent to no designation at all, in light of the Prophet’s statement: “Every condition not found in the Book of Allah is invalid.” (1) Once it is invalid, it has no legal effect. Accordingly, the designation is as though no dowry had been specified, and he is obliged to give her a consolatory gift, as Allah, Most High, says:

“And provide for them.” [Quran 2:236]