فَقِيهٌ وَاحِدٌ أَشَدُّ عَلَى الشَّيْطَانِ مِنْ أَلْفِ عَابِدٍ (Tirmidhi)
Translation: One person with sound understanding of religion is more formidable against Satan than a thousand worshippers.
فَقِيهٌ — a person with deep religious understanding; عَابِدٍ — a worshipper; أَشَدُّ — stronger or more formidable; أَلْفِ — a thousand.
Brief grammar: In فَقِيهٌ وَاحِدٌ, وَاحِدٌ describes فَقِيهٌ. أَشَدُّ ... مِنْ makes a comparison, “more formidable than.”
A person with sound understanding can recognize confusion and guide conduct, so knowledge benefits both the learner and others.