The word “appointed” was explained by the early generations as meaning “prescribed,” and they also explained it as meaning “that which has a fixed time.” What is prescribed is measured out and delimited, for the terms timing, measuring, delimiting, and prescribing are closely related. This requires that the prayer be measured out, delimited, prescribed, and timed, with respect both to its time and its acts. Just as its time is delimited, its acts are all the more deserving of being delimited and timed. This encompasses determining the number of prayers: He made them five, making some four units while resident and two while travelling, some three, and some two both while resident and travelling. It also encompasses prescribing how they are performed.

For this reason, when there is a valid excuse, it is permissible to combine prayers, which entails a kind of advancing and delaying in time. It is likewise permissible to shorten them in number and manner, in accordance with what the revealed law has prescribed. This too is precisely determined when there is an excuse, just as it is determined when there is none. Therefore, one who combines two prayers may not delay a daytime prayer until night or a nighttime prayer until day. The two daytime prayers are the noon and afternoon prayers, while the two nighttime prayers are the sunset and evening prayers. Likewise, the reduction in number and manner permitted to those with valid excuses is fixed and delimited.

Moreover, the acts must have defined beginnings and ends. Thus, standing is defined by an upright posture. If a person voluntarily passes beyond the bounds of uprightness into the bent posture of bowing, he has not fulfilled the required measure of standing.

It is well known that the remembrance uttered while standing—namely, the recitation—is superior to the remembrance uttered while bowing and prostrating. Yet bowing and prostration as acts in themselves are superior to the act of standing. For this reason, the act itself constitutes worship and, under our revealed law, may in no respect be validly directed to anyone but Allah. There are also other proofs mentioned elsewhere.

Given this, it is evident that these acts are measured out and delimited