Charles Ellicott Commentary Proverbs 18:19

"A brother offended [is harder to be won] than a strong city; And [such] contentions are like the bars of a castle." — Proverbs 18:19 (ASV)

A brother offended.— Or rather, wronged.

Their contentions.— Of those who have once been friends, “are like the bars of a castle,” or palace, forming an almost impassable barrier to reconciliation. The bitterness of quarrels between friends is proverbial.