It means: people with uncertain ambitions cannot exert their wisdom. This sentence is from Mo Zi's Self-cultivation, and the original text is as follows:

If you are not strong, you are not wise; People who don't believe in words can't do it. Those who cannot divide people according to wealth are not friends; Those who don't keep the Tao, those who know everything, those who don't observe right and wrong, don't swim.

Translation:

People who have no determination will not have wisdom, and people who have no credit will not have results. It's not worth making friends with someone who owns property but can't share it with others. People who can't keep principles, can't distinguish things widely, and can't distinguish right from wrong are not worth making friends.

Extended data:

This paper mainly discusses moral cultivation and gentleman's personality, emphasizing that moral cultivation is the foundation of governing the country, and gentlemen must attach importance to moral cultivation.

Taking fighting, mourning and learning as examples, the author shows that they are not array, etiquette and talent at all, but courage, sadness and virtue respectively. The author concludes that the first generation of holy kings ruled the world mainly by observing the distance, that is, observing the people around them, attracting gentlemen and sages from afar, and letting them influence each other and serve the country together.

The author believes that "the way of a gentleman" includes "honesty in poverty, righteousness in wealth, love in life and sorrow in death", and observing right and wrong clearly, paying attention to credit and reality.

The author points out that only saints can practice these four things well. Therefore, he put forward some practical self-cultivation standards, such as "a wise man will argue new things without complicated words, exert more efforts without cutting merit", "doing things for wisdom, doing things for literature, and observing things for things". He believes that only in this way can we become a real famous scholar without establishing a false reputation.