The answer is: Evil men

Ps 140:1-3

In Psalm 140, David uses vivid imagery, portraying wickedness with the metaphor of adders—snakes known for their poisonous bites. By saying "adders' poison is under their lips," he’s underscoring the danger posed by deceitful words. Think about the way venom can quickly spread through the body; similarly, careless or malicious speech can do significant harm to relationships and communities.

David is reflecting on the impact of evil men, those who spread lies and deceptions. The reference to adders not only strikes a chord with the reader’s imagination but also connects to the broader biblical narrative where serpents are often symbols of evil and temptation. For example, the cunning serpent of Genesis, who led to the fall from grace, serves as an emblem for deceit throughout time.

Interestingly, in other parts of the Bible, the imagery of animals like adders and serpents appears repeatedly to symbolize danger and treachery. For instance, in Matthew, we see Jesus describe false prophets as "ravenous wolves." This consistent use of animal metaphors reinforces how, throughout scripture, the principles of honesty and virtue are prized above guile and deception.

So, while David’s words created an image of immediate danger in his time, they remind us today to be discerning about the words we speak and the trustworthiness of those around us. Just as animals can evoke certain fears or cautions, these themes provoke thoughtful reflection on morality in all of our interactions.