John Trapp on Amos 1:9

Verſe 9. For three tranſgreſſions of Tyrus] That crown of the ſea Eſay. 23.8. mediâ inſuperabilis undâ, till Alexanders time, who joyned it to Continent, and afterwards ruined it. Charged it is here, as thoſe before, 1. with incurable obſtinacy. 2. with extreame cruelty.

becauſe they delivered up the whole captivity] which either themſelves had taken, or that had fled to them for refuge in ſome common calamity: but were betrayed by them into the hands of their bittereſt enemies. See verſe 6. and acknowledge the truth of that divine proverb. The tender mercies of the wicked are cruel: they help their clients no otherwiſe, then the wolfe in the fable helped the ſheep of his cough, by ſucking his blood.

and have not remembred the brotherly covenant] that paſſed of old betwixt David Solomon, and Hiram their king. Or rather, that between Jacob and Eſau and their reſpective poſterity, which the Tyrians ſhould have promoted by labouring a reconciliation betwixt theſe diſſenting brethren: but they contrariwiſe blew up the coales, and rather ſtirred up more ſtrife then ſtinted it. They called not to mind what unity and amity ought to be between people ſo neer allyed: and what good offices they ſhould therefore have done for them. Protinus indigni fraternum rumpere foedus.Horat. Thou ſhalt not abhorr an Edomite, for he is thy brother. This is Gods argument to Iſrael Deut. 23.8. Should not the Tyrians have ſaid the like to the Edomites, and ſo ſought to have pacified them, rather then gratified them in their hereditary hatred, and deadly feud &c. they put themſelves amongſt thoſe worſt of men, which, given over of God, though they know the law, how that they which commit ſuch things are worthy of death, yet not only do the ſame, but alſo take pleaſure in thoſe that do them Rom. 1. vlt.