A brother offended is harder to be won than a strong city: and their contentions are like the bars of a castle.
The proverb seems extreme. Is it so difficult to reconcile an offended brother? Is there so little hope of recovery once a close relationship is damaged? Strong cities are seldom taken; and castle bars are of the strongest sort. Solomon's inspired wisdom teaches that once you offend a brother, you are in a near hopeless situation. Lord, have mercy!
What causes the rupture to be so severe? It is a rule of nature that offending those who love you may create hatred. Because they gave you their affection, loyalty, service, and trust, the offence strikes deeper in their soul and requires more repair than if done by an acquaintance or stranger. Small offences can ignite family or marital feuds, though such insignificant things would be easily ignored in other relationships. It is a disgusting fact of man's perversity that he often shows less mercy to family and friends than to strangers.
Consider offences between brothers in Scripture. Cain killed Abel for offence at his righteousness. Esau sought to kill Jacob for obtaining his blessing. Joseph's envious brothers sold him into slavery. Absalom plotted two years before killing Amnon for raping his sister. The tribes of Benjamin and Judah had separate costly feuds with Israel.
Barnabas and Paul had a sharp contention about taking Mark on their second preaching trip (Acts 15:36-41). Paul, the most diligent apostle, could not forget Mark's desertion on their first trip (Acts 13:13). Barnabas, Mark's uncle, was offended by Paul's rejection of his sister's son (Col 4:10). Two great saints, who had been close companions, now went their separate ways (Acts 9:27; 11:25; 13:1-2; 14:14; 15:2,25,35). Lord, have mercy!
The wisdom here is to avoid offences with brethren, especially in the church (Eph 4:3,16; Rom 14:16-19; Jas 3:18). Since a close relationship is difficult to recover from offences, it is better to avoid them in the first place. Use great caution in dealing with friends, lest a line be crossed that destroys or scars the relationship, especially in the church.
If you have offended a brother, it is your duty to be reconciled as quickly as possible (Matt 5:23-26). If you have been offended, it is your duty to overlook the transgression or follow an orderly procedure to solve it (Pr 19:11; Matt 18:15-17; I Cor 6:1-8; I Pet 4:8).
The proverb is a natural law. It does not justify godly men being slow to forgive their offenders. Nor does it justify godly men giving up the pursuit of a wounded brother. A spiritual man does not live by natural laws. He lives by the Spirit of God, which teaches him to be slow to wrath and quick to forgive (Col 3:12-13; Jas 1:19). Lord, have mercy!