The meaning of the first clause is obtained in the King James Version by the insertion of the words in italics, and it seems on the whole to be the best. The Septuagint and Vulgate give an entirely different rendering, based, apparently, upon a different text.

A brother offended is harder to be won than a strong city - Almost all the versions agree in the following reading: "A brother assisted by a brother, is like a fortified city; and their decisions are like the bars of a city." Coverdale is both plain and terse: "The unitie of brethren is stronger then a castell, and they that holde together are like the barre of a palace." The fable of the dying father, his sons, and the bundle of faggots, illustrates this proverb. Unity among brethren makes them invincible; small things grow great by concord. If we take the words according to the common version, we see them express what, alas! we know to be too generally true: that when brothers fall out, it is with extreme difficulty that they can be reconciled. And fraternal enmities are generally strong and inveterate.

A brother offended [is harder to be won] than a strong city: and [their] contentions [are] like the (n) bars of a castle.
(n) Which for the strength of it will not bow or yield.

A brother offended is harder to be won than a strong city,.... A fortified city may sooner be taken by an enemy, than one brother offended can be reconciled to another; their resentments against each other are keener than against another person that has offended them; and their love being turned into hatred, it is more bitter; and it is more difficult to compose differences between brethren than between enemies; wherefore such should take care that they fall not out by the way: this is true of brethren in a natural sense; as the cases of Abel and Cain, Jacob and Esau, Joseph and his brethren, Amnon and Absalom, and others, show; and of brethren in a spiritual sense, as Paul and Barnabas, Luther and Calvin, and others;
and their contentions are like the bars of a castle: which cannot be easily broken or cut asunder: so contentions, especially those among brethren, are with great difficulty made to cease, and their differences composed; they will stand it out against one another as long as a strong city, or a barred castle, against an enemy.

Great care must be taken to prevent quarrels among relations and those under obligations to each other. Wisdom and grace make it easy to forgive; but corruption makes it difficult.

No feuds so difficult of adjustment as those of relatives; hence great care should be used to avoid them.

19 A brother toward whom it has been acted perfidiously resists more than a strong tower;
And contentions are like the bar of a palace.
Luther rightly regarded the word נושׁע, according to which the lxx, Vulg., and Syr. translated frater qui adjuvatur a fratre, as an incorrect reading; one would rather expect אח מושׁיע, "a brother who stands by," as Luther earlier translated; and besides, נושׁע does not properly mean adjuvari, but salvari. His translation -
Ein verletzt Bruder helt herter denn eine feste Stad,
Und Zanck helt herter, denn rigel am Palast
[a brother wounded resisteth more than a strong city, and strife resisteth more than bolts in the palace], is one of his most happy renderings. מקּרית־עז in itself only means ὑπὲρ πόλιν ὀχυράν (Venet.); the noun-adjective (cf. Isaiah 10:10) to be supplied is to be understood to עז: עז הוּא or קשׁה הוא (Kimchi). The Niph. נפשׁע occurs only here. If one reads נפשׁע, then it means one who is treated falsely = נפשׁע בּו, like the frequently occurring קמי, my rising up ones = קמים עלי, those that rise up against me; but Codd. (Also Baer's Cod. jaman.) and old editions have נפשׁע, which, as we have above translated, gives an impersonal attributive clause; the former: frater perfidiose tractatus (Fl.: mala fide offensus); the latter: perfide actum est, scil. בּו in eum = in quem perfide actum. אח is, after Proverbs 17:17, a friend in the highest sense of the word; פשׁע means to break off, to break free, with ב or על of him on whom the action terminates. That the פּשׁע is to be thought of as אח of the אח נפשׁע is obvious; the translation, "brothers who break with one another" (Gesen.), is incorrect: אח is not collective, and still less is נפשׁע a reciprocum. The relation of אח is the same as that of אלּוּף, Proverbs 16:28. The Targum (improving the Peshito) translates אחא דמת עוי מן אחוי, which does not mean: a brother who renounces (Hitzig), but who is treated wickedly on the part of, his brother. That is correct; on the contrary, Ewald's "a brother resists more than..." proceeds from a meaning of פשׁע which it has not; and Bertheau gives, with Schultens, an untenable
(Note: Among the whole Hebrews. synon. for sinning, there exists no reflexive Niph.; and also the Arab. fsḳ has no ethical signification. נסכּל only, in the sense of fool, is found.)
reflexive meaning to the Niph. (which as denom. might mean "covered with crime," Venet. πλημμεληθείς), and, moreover, one that is too weak, for he translates, "a brother is more obstinate then...." Hitzig corrects אחז פּשׁע, to shut up sin = to hold it fettered; but that is not correct Hebrews. It ought to be עצר, כּבשׁ, or רדות. In 19a the force of the substantival clause lies in the מן (more than, i.e., harder = more difficult to be gained), and in 19b in the כּ; cf. Micah 7:4, where they are interchanged. The parallelism is synonymous: strifes and lawsuits between those who had been friends form as insurmountable a hindrance to their reconciliation, are as difficult to be raised, as the great bars at the gate of a castle (Fl.). The point of comparison is not only the weight of the cross-beam (from ברח, crosswise, across, to go across the field), but also the shutting up of the access. Strife forms a partition wall between such as once stood near each other, and so much thicker the closer they once stood.
With Proverbs 18:19, the series of proverbs which began with that of the flatterer closes. The catchword אח, which occurred at its commencement, 9b, is repeated at its close, and serves also as a landmark of the group following Proverbs 18:20-24. The proverb of the breach of friendship and of contentions is followed by one of the reaction of the use of the tongue on the man himself.