50:40Qaaf

(This verse means) the prayer and vigil at night.

"The Prophet (S) stood (in prayer) with an Ayah from the Qur'an at night"

He prayed beside the Prophet (ﷺ) one night. He recited, and when he came to a verse that mentioned punishment, he would pause and seek refuge with Allah; if he came to a verse that mentioned mercy, he would pause for mercy. In his bowing he would say: 'Subhana Rabbil-Azim (Glory be to my Lord Almighty)' and in his prostration he would say: 'Subhan Rabbil-A'la (Glory be to my Lord the Most High).'"

“Our Lord, the Blessed and Exalted, descends when one third of the night remains, every night and He says: ‘Who will ask of Me, that I may give him? Who will call upon Me, that I may answer him? Who will ask My forgiveness, that I may forgive him?’ until dawn comes.” Hence they used to prefer voluntary prayers at the end of the night rather than at the beginning.

The Messenger of Allah (ﷺ) prostrated himself at night when reciting the Qur'an. He said repeatedly: My face prostrates itself to Him Who created it and brought forth its hearing and seeing by His might and power.