What is the name of the Surah that contains the verse: (Perform the prayer at the declining of the sun until the darkness of the night), and what is its interpretation?

The exegetes unanimously agreed that the Almighty's saying: "Establish prayer at the declining of the sun until the darkness of the night, and [observe] the Qur’an of dawn. Indeed, the Qur’an of dawn is ever witnessed" includes the obligatory prayers. "The declining of the sun" is its passing its zenith, and it includes the Dhuhr, Asr, Maghrib, and Isha prayers. As for "the Qur’an of dawn," it means the Fajr prayer.