The Difference Between a Defective Marriage Contract and an Invalid Marriage Contract

Question:
Honorable Shaykh, what is the difference between a defective marriage contract (fasid) and an invalid marriage contract (batil), with examples?

Answer:
A defective marriage contract is one in which one of its conditions is lacking. This is the defective contract. An invalid contract is one in which one of its pillars is lacking, such as the absence of the offer or the absence of the acceptance. This is invalid. If a man marries a woman who is in her waiting period ('iddah) from a divorce by someone other than her husband, this is invalid. If he marries a fifth woman when he already has four wives, this is an invalid contract. If a Muslim marries a non-Muslim woman who is not from the People of the Book, this is invalid. And so on; these are invalid contracts. Intercourse in them is considered unlawful sexual intercourse (zina) and fornication. This is unlike the defective contract, where intercourse is considered to be under a doubt (shubhah). It is under a doubt. And the children are attributed to him because his intercourse was under a doubt. As for the invalid contract, the children are not attributed to him because it is fornication. If he marries a fifth woman and she bears him children, they are not attributed to him because it is a contract of fornication. If he marries a woman who is in her waiting period, this is also a contract of fornication, and her children are not attributed to him. And so on; in an invalid contract, the children are not attributed to him because it is fornication. As for the defective contract, the children are attributed to him due to the presence of doubt, because some scholars consider the contract valid. So, given the existence of this disagreement, this constitutes a doubt. This is unlike the invalid contract, regarding which there is consensus that it is not valid.