Leonardo’s remark suggests that the value of advice depends partly on the character and conduct of the person giving it. Someone who manages their own behaviour with discipline and sound judgement may be better placed to offer useful guidance to others. The emphasis is therefore not simply on knowledge, but on whether a person applies good judgement in their own life.

The statement connects credibility with self-governance. A person who can regulate impulses, make considered decisions and act consistently demonstrates qualities that may make their counsel more reliable. This does not mean that disciplined people are always correct, but it offers a practical criterion for deciding whose judgement deserves attention.

The quote can be applied when choosing mentors, advisers or trusted confidants. It encourages looking beyond confident words or reputation and considering whether a person’s own conduct provides evidence of the qualities they recommend to others.

Alternative translation

“Ask counsel of him who rules himself well.”