When we arrived in Madinah, we were struck by a severe outbreak of its fever. The Messenger of Allah ﷺ came out to the people while they were performing their voluntary prayers sitting down, and he said, "The prayer of one who sits is half the prayer of one who stands."
و حدثني عن مالك عن ابن شهاب
لما قدمنا المدينة نالنا وباء من وعكها شديد فخرج رسول الله ﷺ على الناس وهم يصلون في سبحتهم قعودا فقال رسول الله ﷺ صلاة القاعد مثل نصف صلاة القائم