Benefit: Is it Better to Pray Sitting in a Chair or Sitting on the Ground for Those Who Cannot Stand?
In the Name of Allāh, the Ever Merciful, the Bestower of Mercy
Answer: The foundation is that he (prays) sitting on the ground. Those who are not able to sit on the ground should sit on a chair, then if he is able to prostrate on the ground—meaning that he sits on a chair at the time of standing in prayer and then prostrates on the ground—it is compulsory that he does so. If he is not able to prostrate on the ground then he gestures the act of prostration with his head and neck [i.e. bowing his neck and head downwards while seated on the chair] and this will suffice him from the [full] prostration on the ground due to the verse of Allāh:
فَاتَّقُوا اللَّـهَ مَا اسْتَطَعْتُمْ
Fear Allāh to the best of your capability.
[Surah al-Taghābun, 64:16]
Source: ظاهرة الصلاة على الكراسي
Translated by: Munīb al-Ṣumālī