'Seventy Years' in the Bible

And this whole land shall be a desolation, and an astonishment; and these nations shall serve the king of Babylon seventy years.

And it shall come to pass, when seventy years are accomplished, that I will punish the king of Babylon, and that nation, saith the LORD, for their iniquity, and the land of the Chaldeans, and will make it perpetual desolations.

For thus saith the LORD, That after seventy years be accomplished at Babylon I will visit you, and perform my good word toward you, in causing you to return to this place.