And those who spend the night for their Lord, prostrating and standing.

This is an exposition of their state in their dealings with their Lord. When Al-Hasan would recite what preceded this, he would say: "This is the description of their day," and when he would recite this [verse], he would say: "This is the description of their night."

Al-baytuta (spending the night) is for the night to overtake you, whether you sleep or do not sleep.

"For their Lord" (li-rabbihim) is related to what follows it, and it was placed first for the sake of the rhythmic ending of the verse (al-fasilah) and for the sake of exclusivity.

"Standing" (qiyaman) is the plural of qa'im (standing) or an infinitive treated as such; that is, they spend the night prostrating and standing for their Lord—Glory be to Him—meaning they spend the night, in whole or in part, in prayer. It has been said: Whoever recites any part of the Quran at night during prayer has spent it prostrating and standing. It has also been said: What is intended by this is the performance of the two rak'ahs after Maghrib and the two rak'ahs after Isha. It has also been said: Whoever performs the shaf' and witr after having prayed the Isha has entered into the generality of the verse. In summary, the verse encourages standing in prayer at night.

Prostration was mentioned before standing, and not the reverse—even though it is later in the act—for the sake of the rhythmic endings (al-fasilah), and because it is the position in which the servant is closest to his Lord—Glory be to Him—contrasting with the refusal of the arrogant toward Him in the words of the Exalted: "And when it is said to them..." [referring to the verse describing the arrogant].

Abu al-Barhasm read it as sujudan (prostrating) on the measure of qu'udan (sitting), which is more consistent with qiyaman (standing).