…having the form of knowledge and truth in the law. You, therefore, who teach another, do you not teach yourself? You who preach that a man should not steal, do you steal? You who say, “Do not commit adultery,” do you commit adultery? You who abhor idols, do you rob temples? You who make your boast in the law, do you dishonor God through breaking the law? (Romans 2:20-23)
And they were astonished at His teaching, for He taught them as one having authority, and not as the scribes. (Mark 1:22)
In teaching ourselves and mastering what we teach we gain true, fruitful, and effective authority.