The Messenger of Allah ﷺ said, "When you lead people in prayer, keep it brief, for among them are the elderly, the weak, and the young."
حدثنا هاشم عن ابن أبي ذئب عن أبي الوليد
قال رسول الله ﷺ إذا أممتم الناس فخففوا فإن فيهم الكبير والضعيف والصغير
Its isnad is sahih, mentioned previously at 10255.