Al-Matalib al-'Aliyah 421 — The command to the imam to keep it light

It is narrated from Sahl bin Abi Umamah bin Sahl that he and his father went to Sayyiduna Anas bin Malik (may Allah be pleased with him) in the time of Umar bin Abd al-Aziz (may Allah have mercy on him), when he was governor, and he (Sayyiduna Anas) led a short prayer, as if it were the prayer of a traveller or close to it. When he gave the salam, the questioner said: 'Yarhamuka Allah' (May Allah have mercy on you), tell us, was this the obligatory prayer or did you offer a voluntary prayer? He replied: "It was indeed the obligatory prayer, and this indeed was the prayer of the Messenger of Allah (peace and blessings be upon him). I have not fallen short in (performing) it except in something I overlooked out of forgetfulness." Indeed, the Messenger of Allah (peace and blessings be upon him) used to say: "Do not be severe on yourselves, lest severity be imposed upon you, for a people were severe on themselves and so severity was imposed upon them. Their remnants are now (found) in the hermitages and monasteries (of the Christians), (as Allah said:) 'And monasticism, which they innovated, We did not prescribe it for them' [Surah al-Hadid: 27]."
Musnad Abi Ya'la: 421, Sunan Abi Dawud: 4904; Allamah al-Albani graded it hasan (good).