'scholar':
True such an expression '70 years of exile' nowhere occurs in the OT but nowhere does' 70 years of Babylonish domination or servitude' occur in the OT.
Jeremiah 25:11–12: And all this land will be reduced to ruins and will become an object of horror, and
these nations will have to serve the king of Babylon for 70 years. 12 “‘But
when 70 years have been fulfilled, I will call to account the king of Babylon and that nation for their
error,’ declares Jehovah, ‘and I will make the land of the Chal·deʹans a desolate wasteland for all time.
Jeremiah 27:6–11: And now I have given all these lands into the hand of my servant King Neb·u·chad·nezʹzar of Babylon; even the wild beasts of the field I have given him to serve him. 7 All the nations will serve him and his son and his grandson until the time for his own land comes, when many nations and great kings will make him their slave.’ 8 “‘“‘If any nation or kingdom refuses to serve
King Neb·u·chad·nezʹzar of Babylon and refuses to put its neck under the yoke of the king of Babylon, I will punish that nation with the sword, with famine, and with pestilence,’ declares Jehovah, ‘until I have finished them off by
his hand.’ 9 “‘“‘Therefore, do not listen to your prophets, your diviners, your dreamers, your magicians, and your sorcerers, who are saying to you: “You will not serve the king of Babylon.” 10 For they are prophesying lies to you, so that you will be taken far away from your land and I will disperse you and you will perish. 11 “‘“‘But the nation that brings its neck under the yoke of the king of Babylon and serves him, I will allow to remain on its land,’ declares Jehovah, ‘to cultivate it and dwell in it.’”’”
Chronicles 36:20: He carried off captive to Babylon those who escaped the sword, and they became servants to him and his sons until the kingdom of Persia began to reign,