They go out of their way to meet their enemies so as not to allow any spark of hostile, judgmental fire into their own hearts. They know that singleness of heart and purpose allows no exaggerated words, no swearing of oaths, including those sworn before authorities or courts. They speak simply and truthfully without idle phrases or rhetoric, saying neither more nor less than what is necessary. God's spirit gives the clarity that makes hostility and enmity impossible. Evil is combated here not by resisting it forcibly, but by not allowing its principles to find their way into life's struggle.
Evil is combated only by means of good, through love.
So also in the realm of human love, complete clarity must rule. No unfaithfulness in human relationships can arise, no greed for variety prompted by lustful desire can take root. This is the Sermon on the Mount. By their works and their fruits you will recognize them. The lamb's nature knows what serves the whole flock.