al-Isrāʾ 17:12

Wa jaʿalna'l-layla wa'l-nahāra āyatayni fa-maḥawnā āyata'l-layli wa jaʿalnā āyata'l-nahāri mubṣiratan li-tabtaghū faḍlan min rabbikum wa li-taʿlamū ʿadada'l-sinīna wa'l-ḥisāb, wa kulla shayʾin faṣṣalnāhu tafṣīlā

"We made the night and the day two signs. We effaced the sign of the night and made the sign of the day one that gives sight: so that you might seek a bounty from your Lord, and might know the number of the years and the reckoning. And We have set out everything in full detail."

The root م-ح-و: to wipe out, to erase the trace of (as writing is erased).

The choice of verb must be recorded, and this is an observation about the language: the verse does not say of the sign of the night "We made it dark" — it says "We effaced it". Darkness is thus described not as something put in place but as something taken away.

مُبْصِرَة — an active participle: that which shows, that which makes seeing possible. (Not what is seen, but what makes one see.)

This word occurs twice in the sūra: here and at 17/59 (wa ātaynā Thamūda'l-nāqata mubṣiratan). The subject of the two occurrences differs: one is the day, the other a miracle. This is a repetition that can be verified within the sūra, and it will be taken up separately at the fifty-ninth verse.

The verse enumerates the reason for the order in three items:

I record this as an observation: all three grounds are things a human being does. The verse presents the order of night and day not as a beauty but as an infrastructure.

And the same order (jaʿala'l-layla wa'l-nahāra khilfatan) was treated at 25/62 in al-Furqān — the ground there was li-man arāda an yadhdhakkara aw arāda shukūrā (for whoever wishes to take heed or wishes to give thanks). The two verses give the same fact with two different grounds:

The same order, one for the inner world and one for the running of life. I rely on that treatment.