A brother offended is harder to be won than a strong city: and their contentions are like the bars of a castle.
– Proverbs 18:19
[T]he word for offended is a strong term, meaning rebelled against, or quarreled with. The strong city and bars of a castle speak of difficult defenses to overcome. A brother could be a familial relation, or at least a close friend. Once offended, it is difficult to truly repair and reconcile the relationship. Wisdom would teach it is far better to not give offense in the first place (Proverbs 16:32).