What does the phrase "Cast the first stone" warn against?

The phrase "Cast the first stone" originates from a biblical context, specifically from the story of Jesus and the woman caught in adultery. In this story, when asked whether the woman should be stoned according to the law, Jesus replies that only someone without sin should be the one to throw the first stone. This emphasizes the idea of hypocrisy—highlighting that individuals should not be quick to judge others for their faults when they themselves are not without sin.

Therefore, the core warning of the phrase is against hypocrisy and judgment. It suggests that one should reflect on their own imperfections before condemning others, promoting an attitude of self-awareness and humility rather than a rush to judgment. This caution against hypocrisy is particularly relevant in moral discussions and social contexts, urging people to consider their own actions before criticizing others.