al-Qaṣaṣ 28:71-73 — سَرْمَدًا: unceasing night, unceasing day

Qul a-raʾaytum in jaʿala'llāhu ʿalaykumu'l-layla sarmadan ilā yawmi'l-qiyāmati man ilāhun ghayru'llāhi yaʾtīkum bi-ḍiyāʾ … Qul a-raʾaytum in jaʿala'llāhu ʿalaykumu'n-nahāra sarmadan … man ilāhun ghayru'llāhi yaʾtīkum bi-laylin taskunūna fīh

"Say: 'If God had made the night unceasing over you until the Day of Resurrection, what god other than God would bring you light?' Say: 'If God had made the day unceasing over you until the Day of Resurrection, what god would bring you a night in which to rest?'"

سَرْمَد — unceasing, continuing without a break. The word occurs in the Qurʾān only in these two verses.

The two questions are exactly symmetrical, and what answers to each must be recorded:

I record this as an observation about the word order: what is asked for against the night is light — that is, sight; what is asked for against the day is stillness — that is, rest. Two distinct needs, in two distinct words.

And the expression taskunūna fīh is worth recording: the root س-ك-ن (sakīna) was treated at al-Fatḥ 48/4. Here the same root comes as the function of the night: coming to rest.

وَمِن رَّحْمَتِهِۦ جَعَلَ لَكُمُ ٱلَّيْلَ وَٱلنَّهَارَ لِتَسْكُنُوا۟ فِيهِ وَلِتَبْتَغُوا۟ مِن فَضْلِهِۦ (73) — and the two questions close with a sentence that joins the two functions: rest and earning.