Imams, keep the prayer light

The imam should shorten the prayer because the weak, sick and old pray behind him.

Narrated by Abu Hurairah

When one of you leads the people in prayer, let him make it light, for among them are the weak, the sick and the old. When he prays alone, let him make it as long as he wishes.

Sahih al-Bukhari 703, Sahih Muslim 467

What this hadith teaches

An imam considers the people behind him. Light does not mean rushed; it means not lengthening beyond what the congregation can bear.

Reference and grade

Grade
Sahih: agreed upon by al-Bukhari and Muslim
Narrator
Abu Hurairah

The hadith in Arabic نص الحديث

إِذَا صَلَّى أَحَدُكُمْ لِلنَّاسِ فَلْيُخَفِّفْ، فَإِنَّ مِنْهُمُ الضَّعِيفَ وَالسَّقِيمَ وَالْكَبِيرَ، وَإِذَا صَلَّى أَحَدُكُمْ لِنَفْسِهِ فَلْيُطَوِّلْ مَا شَاءَ

Arabic text of Sahih al-Bukhari 703, as given on sunnah.com.