لَيْسَ بِعَرَضٍ وَلَا مُسْتَحِيلَ الْبَقَاءِ
It is not an accident, nor something incapable of subsisting.
In the classical theological vocabulary, an accident (ʿaraḍ) is a dependent property discussed in connection with created subjects and originating states. Treating divine life or knowledge as such a state would import a beginning, need for a contingent locus, or loss of the attribute.
The attributes subsist in the divine essence, not in an externally separate subject. Yet subsisting in the essence does not turn an attribute into a second independently existing divine essence.