Sahih al-Bukhari Book 10, Hadith 99
A man came and said, "O Allah's Messenger (ﷺ)! I keep away from the morning prayer because so-and-so
(Imam) prolongs it too much." Allah's Messenger (ﷺ) became furious and I had never seen him more furious
than he was on that day. The Prophet (ﷺ) said, "O people! Some of you make others dislike the prayer, so
whoever becomes an Imam he should shorten the prayer, as behind him are the weak, the old and the
needy.''
Allah's Messenger (ﷺ) said, "If anyone of you leads the people in the prayer, he should shorten it for amongst them are the weak, the sick and the old; and if anyone among your prays alone then he may prolong (the prayer) as much as he wishes. "
Once a man was driving two Nadihas (camels used for agricultural purposes) and night had fallen. He found Mu`adh praying so he made his camel kneel and joined Mu`adh in the prayer. The latter recited Surat 'Al-Baqara" or Surat "An-Nisa", (so) the man left the prayer and went away. When he came to know that Mu`adh had criticized him, he went to the Prophet, and complained against Mu`adh. The Prophet said thrice, "O Mu`adh ! Are you putting the people to trial?" It would have been better if you had recited "Sabbih Isma Rabbika-l-A`la (87)", Wash-shamsi wa duhaha (91)", or "Wal-laili idha yaghsha (92)", for the old, the weak and the needy pray behind you." Jabir said that Mu`adh recited Sura Al-Baqara in the `Isha' prayer.