Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.140.

Section : Sunnah acts of prayer, The Recitation in the Noon Prayers.

He would sometimes make this recitation lengthy. Abu Sa’eed even once said, “While he was standing in the noon prayer, one could go to al-Baqi’e and take care of some matter, return to his family, make ablution, return, and still find the Prophet, upon whom be peace, in the first rak’ah due to the length of his recital.” (Related by Muslim.) He would sometimes recite all of Alif, Lam, Mim, Tanzil, or al-A’la, or al-Lail, or sometimes al-Buruj or at-Tariq.