Definition & Meaning of "do as I say and not as I do"

What is the origin of the proverb "do as I say and not as I do" and when to use it?

‌The proverb "do as I say and not as I do" first appeared in John Selden's 'Table-Talk,' where he noted, "Preachers say, 'Do as I say, not as I do.'" The concept aligns with a passage from the New Testament (Matthew 23:1-3; King James Version), in which Jesus cautions against following the hypocritical actions of the scribes. It also serves as a reminder that true leadership and advice should be consistent and align with personal actions. It warns against relying solely on advice from those who do not practice what they preach, as this can undermine the effectiveness of their guidance.