The well-worn, some would say overworn, phrase “hate the sin, love the sinner” has been the subject of a lot of criticism in recent years. Indeed, I rarely hear it anymore except as people are introducing the phrase in order to attack it.
But Christ teaches, that we ought not, for any cause, to be so angry as to call any man Raca, or fool. We ought not, for any cause, to be angry at the person of the sinner, but at his sins only. Happy world, were this plain and necessary distinction thoroughly understood, remembered, practised!
The point Wesley is making is, I think, the same point that many who don’t like the “hate the sin, love the sinner” talk. Wesley is saying that we should never use harsh or angry words with a person, even though we find the sin provoking. We should treat the sinner with sincere love and kindness and gentleness. Indeed, as we ourselves are sinners, doing so is nothing more than following the Golden Rule. If we do not, then we run afoul of our Lord’s teaching.