Jeremiah 25:11-12
11. seventy years— (Jer 27:7). The exact number of years of Sabbaths in four hundred ninety years, the period from Saul to the Babylonian captivity; righteous retribution for their violation of the Sabbath (Le 26:34, 35; 2Ch 36:21). The seventy years probably begin from the fourth year of Jehoiakim, when Jerusalem was first captured, and many captives, as well as the treasures of the temple, were carried away; they end with the first year of Cyrus, who, on taking Babylon, issued an edict for the restoration of the Jews (Ezr 1:1). Daniel's seventy prophetic weeks are based on the seventy years of the captivity (compare Da 9:2, 24).
Jeremiah 27:7
7. son . . . son's son— (2Ch 36:20). Nebuchadnezzar had four successors—Evil-merodach, his son; Neriglissar, husband of Nebuchadnezzar's daughter; his son, Labosodarchod; and Naboned (with whom his son, Belshazzar, was joint king), son of Evil-merodach. But Neriglissar and Labosodarchod were not in the direct male line; so that the prophecy held good to "his son and his son's son," and the intermediate two are omitted.
time of his land—that is, of its subjugation or its being "visited" in wrath (Jer 27:22; Jer 25:12; 29:10; 50:27; Da 5:26). serve themselves of him—make him their servant (Jer 25:14; Isa 13:22). So "his day" for the destined day of his calamity (Job 18:20).Jeremiah 29:10
10. (See on Jer 25:11; Jer 25:12; Da 9:2). This proves that the seventy years date from Jeconiah's captivity, not from the last captivity. The specification of time was to curb the impatience of the Jews lest they should hasten before God's time.
good word—promise of a return.