In our study of Isaiah chapter twenty three, we see that God will judge people based on how they treat His children.
"A prophecy against Tyre: Wail, you ships of Tarshish! For Tyre is destroyed and left without house or harbor. From the land of Cyprus word has come to them." NIV translation
Tyre was the chief city of the Phoenicians and they were known for their making and sailing of ships.
Cyprus is an island to the west of Tyre in the Mediterranean Ocean. Many of the ships that were heading to Tyre would have passed by Cyprus on their way. Here, we are not told why Tyre was going to be judged but we know the answer from Ezekiel 26. When Judah was taken into captivity by Babylon, Tyre had rejoiced and saw business opportunities. This was, in effect, cursing Israel and, because of God's promise to Abraham (in Genesis 12:3), He was obligated to judge Tyre for it.
"Be silent, you people of the island and you merchants of Sidon, whom the seafarers have enriched. On the great waters came the grain of the Sihor; the harvest of the Nile was the revenue of Tyre, and she became the marketplace of the nations." NIV translation
Tyre consisted of settlements of the mainland of Lebanon as well as a fortified island off the coast.
Sidon had been the chief city and the mother of Tyre but was quickly surpassed by Tyre as the chief city. The people of Sidon and Tyre were made rich by their shipping empire.
Egypt and all of the other nations in the area used the Phoenician ships to transport their grain and other merchandise.
"Be ashamed, Sidon, and you fortress of the sea, for the sea has spoken: 'I have neither been in labor nor given birth; I have neither reared sons nor brought up daughters.'" NIV translation
The Phoenicians thought that they had a natural ability and right to rule the seas. In this verse, they are reminded that it is the God of Israel that gives people their talents and abilities.
The same type of thing happens today as many people become famous for one thing or another but do not acknowledge that it is God that gave them the talent. Some even go so far as to ridicule Christians who give God the credit for their success. Like, Tyre, they too will be judged for their treatment of God's children.