وَأَصْلُ الْقَدَرِ سِرُّ اللَّهِ تَعَالَى فِي خَلْقِهِ
The foundation of predestination is Allah Most High’s secret concerning His creation.
Clause structure: Sirr Allāh is a construct phrase describing decree as a divine secret. Fī khalqihi locates the matter in relation to His creation.
Meaning and inference: The deepest aspects of divine decree cannot responsibly be defined with unwarranted certainty by human speculation.
Limit of inference: Unknowable depths of decree do not remove belief in decree, its established principles, or human moral responsibility.