A buddha bis a liberated being who has attained complete mastery. A buddha can teach in any given situation and is never rattled by any difficulty a buddha needs no code of conduct set of rules or guidelines or manual of behavior os his understanding can handle any situation without reference to such codes.
The ago or tne sense of being a separate individual is one hindrance in eliminating defilements for as long as a being believes in his uniqueness and refuses to surrender his separateness in thought and action he will remain unaware of buddha nature and will continue suffering in samsara and creating suffering for other.
Before breathing his last the historical buddha reminded his pupils that all compounded things are subject to decay the fear of impermanence is eliminating when it is properly comprehended and eventually the need to defend what is temporary diminishes.