al-Muʾminūn 23:73-74

wa innaka la-tadʿūhum ilā ṣirāṭin mustaqīm · wa inna'lladhīna lā yuʾminūna bi'l-ākhirati ʿani'l-ṣirāṭi la-nākibūn

"You are indeed calling them to a straight path. And those who do not believe in the hereafter are turning aside from the path."

The construction was treated in detail in al-Fātiḥa. I do not repeat it here.

What belongs here is the difference of definiteness between the two verses, and it must be recorded:

The seventy-fourth verse takes back with the article alif-lām the path named in the verse before. In Arabic this is an operation called ʿahd dhikrī: a thing first mentioned indefinitely is then repeated as definite. The lexicographers record this consistently.

The concrete sense of the root: to swerve to one side, to slip sideways. Mankib — the shoulder (the side of the trunk); nakbāʾ — the wind that blows from between the cardinal directions; nakba — a calamity (falling off the road).

The root is worked out here for the first time in this series.

And a comparison with tankiṣūn in the sixty-sixth verse is worth recording, because the two words are close in sound but are separate roots:

That the two roots are separate is certain, and I build no derivational link between them. The note of caution entered for roots close in sound in ʿAbasa and al-Muṭaffifīn holds here as well.

But that the two words stand in the same sūra, eight verses apart, is a datum, and I record it as an observation: the sūra names two distinct ways of leaving the road — drawing back, and swerving aside. The first is staying on the road and not advancing; the second is leaving the road.

And the condition must be recorded: not believing in the hereafter is given as the ground of the swerving.

This is on the same line as the finding recorded at al-Furqān 25/11: bal kadhdhabū bi'l-sāʿa — "that is not the real matter: they denied the Hour." I rely on that treatment.

The two sūras make the same diagnosis: beneath the objections that are voiced lies an unvoiced rejection of the hereafter. And al-Muʾminūn had done the same in the thirty-third verse: wa kadhdhabū bi-liqāʾi'l-ākhira.

The same diagnosis, in two places.