Must a person who can stand but is unable to perform bowing (ruku') or prostration (sujud) perform the standing posture during obligatory prayer?
Chapter on the Times When Prayer is Prohibited
Al-Mughni
Book of Prayer
Primary text
The standing posture remains obligatory for one who can stand but cannot perform bowing or prostration. Such an individual must pray standing, using gestures (pointing/nodding) for bowing, then sit, and use gestures for prostration. This view is held by Al-Shafi'i. The evidence supporting this obligation is the command of Allah the Almighty: "And stand up before Allah in obedience" (Quran 2:238), and the statement of the Prophet (peace be upon him): "Pray standing." Furthermore, since standing is a pillar (rukn) that the person is capable of performing, it must be executed, similar to recitation. Inability to perform other actions does not necessitate the dropping of standing, just as inability to recite does not negate the obligation to stand.
Supporting text
Abu Hanifa holds that the standing posture is waived for this person. His reasoning is that this prayer lacks both bowing and prostration, thus the standing posture is waived, analogous to optional prayers performed on a mount. This reasoning is refuted because bowing is not waived in prayer on a mount, optional prayer does not mandate standing, and funeral prayer serves as a counterexample.