Charles Ellicott Commentary Jeremiah 27:7

"And all the nations shall serve him, and his son, and his son`s son, until the time of his own land come: and then many nations and great kings shall make him their bondman." — Jeremiah 27:7 (ASV)

And his son, and his son’s son. —The words may have had the meaning that this was to be the farthest limit of Nebuchadnezzar’s dynasty, as defined by the seventy years of Jeremiah 25:11. The use of the phrase, however, in Exodus 34:7, Deuteronomy 4:25, points rather to an undefined prolongation, subject only to the fact that there was an appointed limit. Historically we may note the fact that Nebuchadnezzar was succeeded by his son, Evil-merodach (Jeremiah 52:31); he by his brother-in-law, Neriglissar, and he by Nabouahid and his son Belshazzar. (See Introduction.)

Shall serve themselves of him. —Better, shall make him to serve. It lies in the nature of the case that the pronoun refers to the King of Babylon for the time being. The confederacy of nations which shall overthrow the Babylonian monarchy, Medes and others, is described more fully in Jeremiah 51:11; Jeremiah 51:27–28. The words were clearly meant to point both ways. They warn the nations not to resist the Chaldean king then. They warn the king not to think that he is founding a dynasty of long duration. The whole verse is missing in the Septuagint, perhaps because they imagined that the son’s son of Jeremiah 27:7 was inconsistent with the facts of history, as they read them.