The Prayer on the chair

He would sit on the chair to pray when he will be not in position to complete the process of Ruku and Sajdah due to reason of injuries or pain or difficulties. If he has capacity to pray standing on earth, he will not sit on the chair. He will stand on the ground to pray with indications.
Warning! There are different kind of the negligence, they begin to pray sitting on the chair due to reason of slightest pretext, they should be well remembered by the aforesaid problem. (Fatwas Tatar khanih, Vol. 2/120)