الْعِلْمُ نُورٌ.
Knowledge is light.
A brief metaphorical assertion can suggest insight, deliverance from ignorance and practical direction. In a context that relies on these wider implications, it illustrates the tendency of ījāz al-qaṣr: broad meaning expressed compactly without having to reconstruct a particular omitted word or clause.
الْعِلْمُ نُورٌ يَهْدِي صَاحِبَهُ إِلَى الرُّشْدِ.
Knowledge is a light that guides its possessor toward sound judgment.
The expansion makes one implication explicit. It is not necessarily defective because it is longer; the rhetorical judgment depends on whether the listener needs that clarification in the given setting.