Albert Barnes Commentary Ezekiel 27:25

"The ships of Tarshish were thy caravans for thy merchandise: and thou wast replenished, and made very glorious in the heart of the seas." — Ezekiel 27:25 (ASV)

Did sing of thee - Or, were your bulwarks, that is, bulwarks of your traffic. Others render it: “were your caravans,” your merchandise.