مُرَاعَاةُ التَّرْتِيبِ الْوُجُودِيِّ
Ordering items in accordance with their usual sequence or relation in occurrence.
لَا تَأْخُذُهُ سِنَةٌ وَلَا نَوْمٌ
Neither drowsiness nor sleep overtakes Him. (Al-Baqarah 2:255)
Sinah is drowsiness or the onset of sleep; nawm is sleep itself. Presenting drowsiness first reflects their familiar sequence in human experience.
The verse negates both conditions of God. The rhetorical observation is that its wording lists the states in a naturally intelligible order.