إِنَّمَا الْعِلْمُ نُورٌ؛ يُهْدِي صَاحِبَهُ، وَيَكْشِفُ لَهُ طَرِيقَهُ.
Knowledge is light: it guides its bearer and reveals the way ahead.
Innamā signals restriction; al-ʿilmu nūr displays the form of an emphatic simile with both compared terms expressed; the two following verbs explain the image. Several rhetorical devices can operate in a single passage.
A strong analysis explains how the light image clarifies guidance and whether the audience actually needs emphatic restriction. Naming multiple devices is only the start of rhetorical judgment.