Fourth: the conditions of marriage are not divided into valid and invalid, whereas conditions stipulated in marriage are divided into valid and invalid.
Know that conditions stipulated in marriage must either accompany the contract or precede it; they cannot be added after it. Their place is therefore either within the contract itself or before it, not after it. An example of a condition included in the contract is for him to say: “I give you my daughter here in marriage on condition that you do not take another wife alongside her.” This accompanies the contract. Or: “I give you my daughter here in marriage on condition that you give her five hundred riyals as a dowry.” This too accompanies the contract. A prior condition is where he and the other party agree, when he proposes for her hand, that he will not take another wife alongside her. Although this condition precedes the contract, they agreed upon it, so it is taken into account, because the contract that was concluded is based on the conditions previously agreed upon.
We have previously mentioned, regarding conditions in a sale, that those which count are the ones accompanying the contract and those added during the option period, not what the two parties agreed upon beforehand. We also previously stated that the sound view is that it is like marriage in this regard, with no difference between them: what they agree upon before the contract is like a condition accompanying it. In marriage, however, a condition cannot be added subsequently, because, according to the established school of law, there is no option period in marriage. In a sale, it may be added after the contract, such as when it is added during the option of the session or the stipulated option period, as mentioned earlier.
Know that the basic principle concerning all conditions in contracts is validity unless evidence establishes their prohibition. The proof for this is the general purport of the texts commanding fulfilment of contracts: “O you who believe, fulfil your contracts.” [al-Ma'idah 5:1] And: “Fulfil every commitment, for every commitment will be questioned about.” [al-Isra' 17:34] Likewise, there is the hadith narrated from the Messenger: