The Book of Waiting Periods
This is one of the most important chapters of jurisprudence, because many issues concerning inheritance, the validity of marriage, and other matters are based upon it.
His statement: “Waiting periods” is the plural of ʿiddah, with a kasrah on the letter ʿayn. Linguistically, it is derived from counting—that is, one, two, three, four, and so on.
In the Sacred Law, it means a legally prescribed period of waiting due to the dissolution of a marriage, or what is treated as equivalent to it.
By our saying, “a period of waiting,” we mean waiting. It is taken from Allah’s saying, “Divorced women shall wait by themselves” [al-Baqarah: 228], and His saying, “Those of you who die and leave wives behind—their wives shall wait by themselves” [al-Baqarah: 234].
By our saying, “legally prescribed,” we mean prescribed by the Sacred Law.
And by our saying, “due to the dissolution of a marriage, or what is treated as equivalent to it,” we mean, for example, intercourse under a mistaken assumption of legality. If a woman is thus had intercourse with, she must observe a waiting period, even though this was not a marriage; it is nevertheless treated as equivalent to one.
As for the ruling on the waiting period, it is obligatory, due to Allah’s saying, “Divorced women shall wait by themselves.” The scholars said: this is a declarative statement intended as a command. It was expressed in the form of a statement in order to affirm and establish it, as though it were a settled and completed matter. Likewise is His saying, “As for pregnant women, their waiting period ends with delivery” [al-Talaq: 4]. Thus, the waiting period is obligatory, but it has conditions. For it to be obligatory, the marriage must not be invalid; and if the separation takes place during the husband’s lifetime, intercourse or seclusion must have occurred between persons capable of having a child together.