Many personal desires are harmless or even good. The test arises when preference pulls someone away from truth, fairness, or an obligation. What the Prophet ﷺ brought supplies the standard for choosing correctly.
Example 1: You dislike someone and feel tempted to conceal testimony that would protect their right. Following guidance requires truthfulness despite resentment.
Example 2: A trader wants more profit but could gain it only by deceiving a customer. Integrity requires keeping that desire within ethical limits.
جِئْتُ is a first-person past-tense verb: “I brought.” The pronoun in بِهِ refers back to what the Messenger brought.