How to get Auriel's Bow - Elder Scrolls: Morrowind
Location: Ghostgate, Tower of Dawn
Requirements: Able to Taunt/Frenzy Humanoid Ralyn into attacking you - otherwise expect to incur the wrath of nearby guards
Video: How to get Auriel's Bow
Auriel's Bow is a non-enchanted very high damage bow which is in the posession of Ralyn Othravel in the town of Ghostgate. You can find Ralyn Othravel in the upper portion of the Tower of Dawn. In order to get the bow from Ralyn you'll need to provoke him into attacking you first (otherwise you'll be charged with Murder) or you can pick pocket it from him since he doesn't have it equipped.
This bow is involved in the Auriel's Bow Side Quest which is part of the House Telvanni quest line. If you're looking for a good bow the Daedric Longbow is much better since it has a higher enchant value - though it has the same base damage as Auriel's Bow.