Isaiah 23:16
Take an harp, go about the city, thou harlot that hast been forgotten; make sweet melody, sing many songs, that thou mayest be remembered. Take an harp, go about the city, thou harlot that hast been forgotten; make sweet melody, sing many songs, that thou mayest be remembered.
Isaiah 23:16 belongs to the prophecy concerning Tyre in Isaiah 23, which is identified as one of the prophecies concerning Tyre. The prophecy foretold that the Chaldeans under Nebuchadnezzar would destroy the city, in a destruction set forth in Isaiah 23:1-18, and that though many of its people would escape they would find no rest in their places of refuge. That destruction by Nebuchadnezzar came before the later destruction by Alexander, when Tyre's stones and timber and dust were thrown into the sea to make a bridge to New Tyre.
Verses 15-17 foretold Tyre's restoration after seventy years, and the fall of the Babylonian Empire gave the city opportunity to rebuild in fulfillment of the prophecy. The forgotten harlot who takes a harp and sings many songs to be remembered portrays Tyre after its restoration as spiritually, not physically, unfaithful, left desolate under judgment and singing to regain attention. After its restoration Tyre returned to its former wickedness, committing fornication with the kings of the earth and using its wealth for evil rather than for God's glory.
In that use of wealth for evil rather than God's glory, Tyre is a type of the apostate church. Tyre would be destroyed again and never regain its former importance. Being remembered and visited again after desolation means God would do a work for her, which happened when a Christian church was raised up in the city of Tyre whose members gave their means and the wealth of Tyre to God, though the city itself did not escape its due punishment. Tyre would eventually be devoted to the worship of the true God and become a place associated with fishermen, which is presented as fulfilled.