Brood of vipers, how can you speak good things when you are evil? For the mouth speaks from the fullness of the heart.
In this saying Jesus addresses the Pharisees and calls them a “brood of vipers,” a severe condemnation meant to highlight their deceit and hypocrisy. He explains that a person’s words reflect the true condition of the heart: a good heart produces good words, and an evil heart produces evil ones. Jesus shows that words are not merely outward expressions, but come from the depths of the heart. The Pharisees, who presented themselves as devout, in reality had evil intentions, and this was expressed through their words. What we say reflects our spiritual, inner condition. Jesus calls people to pay attention to the state of their hearts, because only a pure heart can produce good words and deeds.