I say, and with God's success: It is recommended that the surahs be long from the long part of the Quran during Fajr and Maghrib, medium during Asr and Isha, and short during Maghrib. From Umm Salamah, may Allah be pleased with her, she said: "I walked behind the people while the Prophet was praying and reciting Surah At-Tur" in Sahih Bukhari 1: 267, and from Amr ibn Hurayth: "He heard the Prophet (peace be upon him) reciting in Fajr: {And the night when it covers} [Al-Takwir: 17]" in Sahih Muslim 1: 336, and from Qutbah ibn Malik, he said: "I prayed and the Messenger of Allah prayed with us and recited: {Qaf, by the glorious Quran} until he recited: {And the palm trees, lofty} [Qaf: 10] he said: So I kept repeating it and did not know what he said" in Sahih Muslim 1: 336. And from Abu Sa'id Al-Khudri: "We used to estimate the standing of the Messenger of Allah in Dhuhr and Asr, and we estimated his standing in the first two rak'ahs of Dhuhr to be about {Alif Lam Meem, the revelation} of Surah As-Sajda" in Sahih Muslim 1: 334. And from Jabir ibn Samurah, may Allah be pleased with him: "The Prophet used to recite in Dhuhr and Asr: {By the sky and the morning star}, and {By the sky, the one with the towers}" in Sunan Abu Dawood 1: 273, and Sunan Al-Darimi 1: 335. And from Jabir, may Allah be pleased with him, he said: "Mu'adh ibn Jabal prayed for his companions the Isha prayer and prolonged it, so one of our men left and informed Mu'adh about him, and he said: 'He is a hypocrite.' When that man heard this, he went to the Messenger of Allah and informed him of what Mu'adh said, so the Prophet said to him: 'Do you want to be a tempter, O Mu'adh? When you lead the people in prayer, recite: {By the sun and its brightness}, and {Glorify the name of your Lord, the Most High}, and {By the night when it covers}, and {Read in the name of your Lord}'' in Sunan Al-Nasa'i Al-Kubra 1: 342. And from Ibn Mas'ud, may Allah be pleased with him: "The Prophet (peace be upon him) used to recite in the two rak'ahs after Maghrib: {Say, O disbelievers}, and {Say, He is Allah, One}'' in Sunan Ibn Majah 1: 369. And Allah knows best.