All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

For the person who is able to stand up during compulsory prayer, standing up is a pillar without which his/her prayer is considered invalid. However, if a person is unable to stand up in prayer, then he/she is allowed to pray sitting, and he/she is free of liability. This applies to the person praying alone, an Imam or those praying behind an Imam. In addition, it is valid to pray behind an Imam who is praying sitting down and their prayer is considered valid. Al-Khateeb Al-Shirbini said: "It is permissible for the prayer performer who made ablution to pray behind the Imam who  made Tayamum*…..It is also permissible for the prayer performer who can stand up in prayer to pray behind the Imam who prays sitting down or lying on his side. The evidence on this is that Bukhari reported that Ayisha narrated that the Messenger of Allah (PBUH), during his death sickness, led prayer sitting down while Abu Baker and other prayer performers prayed standing.

While standing, the prayer performers must follow the transitions of the Imam, and go into ruku and sujud in their known forms. This is the view of the majority of the scholars based on the narration of Aisha upon the sickness of the Prophet (PBUH): The Prophet (PBUH) sat on his left side. Abu Bakr was praying while standing and Allah's Messenger (PBUH) was leading the prayer while sitting. Abu Bakr was following the Prophet (PBUH) and the people were following Abu Bakr (in the prayer).'{Related by Bukhari}.

Scholars added that this Hadith was in the last days of the Prophet`s life. Therefore, it abrogates the Hadith of Jaber (…….and if he prays sitting down then pray sitting down). 

After having related this Hadith, Imam Bukhari said that Al-Humaidi said, "The Hadith of Jaber is abrogated because the Prophet (PBUH), in the last part of his life, prayed sitting while people followed him standing.

Ibn Hajar{May Allah have mercy on him} said, "The Hadith related by Bukhari was adopted as basis for abrogating the order to pray sitting when the Imam is sitting {Hadith Jaber}, because the Prophet (PBUH) has approved of the companions` praying standing while he led them in prayer sitting. This is the view of Al-Shafie, Abu Hanifah, Abu Yusuf, and Al-`Awzaa`ei. The Hadith was also reported by Al-Waleed Bin Moslim from Imam Malik. However, Imam Ahmad didn`t follow this view and said that each Hadith applies to a special case.{Fateh Al-Bari, V.2/P.176}.

In conclusion, the prayer of the Imam who leads the prayer sitting down due to a valid excuse is valid for both himself and those praying behind him.

 

*(Tayammum consists of using clean soil or dust to wipe your face and hands with the intention of preparing oneself to pray, and, as such, substitutes wudoo in special circumstances) and isn`t required to rpeat prayer after having access to water).