2 Kingdoms (2 Samuel) 20:9Meaning & Commentary from the Church Fathers

Let us consider those who pursue just vengeance. It is clear to all that those who wrong their neighbors are, in reality, harming themselves, ranking among the lowest. Yet, who rightly exacted revenge, incited numerous evils, and invited upon himself considerable troubles and grief? The commander of David. He engaged in fierce battles and endured countless afflictions, all of which could have been avoided had he acted wisely. Therefore, let us refrain from this sin and strive not to wrong our neighbors in our words or actions.

Men can be quite treacherous, for their wickedness is not expressed openly but is hidden within them. Their speech may seem charming, yet their hearts plot malice. Therefore, Joab grasped Amessai's beard with his right hand, while with his left hand he stealthily reached for his sword, resulting in Amessai's bowels spilling onto the ground. Grasping his chin with his right hand appears as a gesture of kindness and warmth. However, his left hand wields the sword, striking Amessai treacherously.

*See Job 20:12-13, which reflects on the idea that if evil tastes sweet to one, it will be harbored and not dismissed.