يُكَوِّرُ ٱلَّيْلَ عَلَى ٱلنَّهَارِ وَيُكَوِّرُ ٱلنَّهَارَ عَلَى ٱلَّيْلِ … يَخْلُقُكُمْ فِى بُطُونِ أُمَّهَٰتِكُمْ خَلْقًا مِّنۢ بَعْدِ خَلْقٍ فِى ظُلُمَٰتٍ ثَلَٰثٍ
"He winds the night over the day, and He winds the day over the night… He creates you in your mothers' wombs, within three darknesses, one creation after another."
The concrete sense of the root: to make a thing round by folding it and winding it. Kawwara'l-ʿimāma — he wound the turban. Kūr — a rounded heap.
The root was analysed in al-Takwīr in connection with the name of that sūra (idha'sh-shamsu kuwwirat), and the word's picture of being wound and rolled up was treated there. I do not repeat it here.
The use here is worth recording, and it runs in two directions: yukawwiru'l-layla ʿala'n-nahāri wa yukawwiru'n-nahāra ʿala'l-layl — each is wound over the other.
Per the method (Method) I draw a limit: I derive from this word no firm conclusion about the shape of the earth or its motion. The dictionary sense of the word is winding and folding; what the verse describes is night and day taking each other's place without a break. To produce a modern cosmology out of this would be to make the text say what it does not say.
"Three darknesses." Differing explanations of what these are are transmitted in the classical commentaries, and none of them is presented as certain knowledge.
What the verse itself gives is this, and that much I record: the forming takes place somewhere unseen, and it takes place by stages — khalqan min baʿdi khalq.
In Ghāfir (al-Muʾmin) at 40/67 the same staged forming had been set out in six steps, and the limit set by the method (Method) was drawn there: these expressions are not to be matched one-to-one with the terms of modern embryology. I keep the same limit here.
How the proof works is plain: man's most basic forming is completed in a place hidden from his own eye. The same line as the one treated in al-Wāqiʿa at 56/58-59: the separation of man's share from the outcome.