The Bible does not specify a precise length of time for Gentile rule. However, the concept of a period of Gentile dominion is drawn from several passages, primarily in the Book of Daniel and the Book of Luke.
* Daniel: In Daniel 2, Nebuchadnezzar's dream of a statue with different metals is interpreted as representing successive kingdoms. Many interpretations see these kingdoms as empires, beginning with Babylon and continuing through Persia, Greece, and Rome. The statue is destroyed by a stone, which is often interpreted as the kingdom of God replacing these earthly kingdoms.
* Luke: In Luke 21:24, Jesus says of Jerusalem, "They will fall by the sword and will be taken as prisoners to all nations. Jerusalem will be trampled on by the Gentiles until the times of the Gentiles are fulfilled."
The phrase "times of the Gentiles" in Luke is often understood as a period during which Gentile nations have dominion over Jerusalem and, by extension, the world. The exact duration of this period is not specified. Different interpretations exist regarding when this period began and when it will end, often linked to events such as the establishment of the modern State of Israel and the future role of Jerusalem.
Due to the ambiguity and differing interpretations, it's impossible to provide a definitive biblical answer for how long Gentile rule will last.