This is the seventh installment from a series of posts aimed at making The Ultimate Conspectus accessible to readers who have never read fiqh before or are looking for a refresher.
2.3.2 Integrals
There are eighteen integrals [arkān] of prayer. Each of them is required of the imam, his follower, or an individual praying alone. The absence of a single one along with its conditions prevents a prayer from being valid. So if a single one is missing, the prayer must be made up. These eighteen are mentioned in their order of occurrence in the prayer.