(a) Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) says that Sayyiduna Mu'adh bin Jabal (may Allah be pleased with him) led his companions in the Isha prayer and made the prayer long. The Prophet (peace and blessings be upon him) was informed of this, and the Prophet (peace and blessings be upon him) said: "O Mu'adh! Are you one who puts people to trial? Make it light for people. Recite these surahs: 'By the sun and its brightness', 'Glorify the name of your Lord, the Most High' and surahs like them, and do not make things hard for people."
(b) In the narration of al-Layth bin Sa'd there is an addition: "Recite: 'Read in the name of your Lord' [Surah al-Alaq: 1], 'By the night when it covers' [Surah al-Layl: 1]," and he did not mention the sentence about not making things hard for people.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5272