The conduct of Tyre was base towards Israel, and now Tyrus comes to be reckoned with. The breach of the brotherly covenant, seems to have an allusion to the friendly compact which had been made between Solomon and Hiram many years before, which we may read 1 Kings 5:12.; and so much friendship was there between them, that Hiram called Solomon brother, 1 Kings 9:13.
Related Commentaries of Amos 1:9
Amos 1:9-10
9 Thus saith the LORD; For three transgressions of Tyrus, and for four, I will not turn away the punishment thereof; because they delivered up the whole captivity to Edom, and remembered not the brotherlyc covenant:
10 But I will send a fire on the wall of Tyrus, which shall devour the palaces thereof.