سَنُقْرِئُكَ فَلَا تَنْسَىٰ ۞ إِلَّا مَا شَاءَ اللَّهُ
We shall cause you to recite, and you will not forget, except what Allah wills. (87:6–7)
The prefix sa- marks futurity, and “you will not forget” is a linked promise, not an ordinary prohibition addressed as “do not forget.” The context of assurance decides the force of lā.
“Except what Allah wills” places the promise under divine will. The exception neither cancels the assurance nor creates a contradiction. Rhetorical precision requires holding the principal statement and its qualification together.