Stop 1. Promises kept inside the Old Testament

Start with the gold arcs. These are places where the Old Testament itself names a prophecy and then records the outcome. No later reader has to make the connection; the text makes it.

The clearest run is in Kings. A man of God stands at Jeroboam's altar and says, "Look, a son named Josiah will be born to the Davidic dynasty" (1 Kings 13:2). Generations later Josiah burns bones on that altar, "just as in the Lord’s message that was announced by the prophet" (2 Kings 23:16). Kings closes the loop on Eli's house, on Jeroboam's dynasty, on Jezebel, and on Jehu's line the same way.

The longest gold arcs belong to the exile. Jeremiah gives a number: the nations "will be subject to the king of Babylon for 70 years" (Jeremiah 25:11). Chronicles ends by saying the exile happened "to fulfill the Lord’s message spoken through Jeremiah" (2 Chronicles 36:21), and Ezra opens with Cyrus's decree "in fulfillment of the Lord’s message spoken through Jeremiah" (Ezra 1:1).

Isaiah names Cyrus outright: "who commissions Cyrus, the one I appointed as shepherd to carry out all my wishes" (Isaiah 44:28). Ezra records the decree that sent the people home to rebuild.

Record check (judgment). Seventy years: from the temple's fall in 587 or 586 BC to the second temple's completion in 516 or 515 BC is 70 to 72 years (calculated from the dates on The Whole Story, Chart 2). Babylon itself fell to Cyrus in 539 BC, one of that chart's outside anchors. Another common reckoning starts at 605 BC, the first deportation, and ends with Cyrus's decree and the first return, 539 to 536 BC. Which reckoning Jeremiah means is itself disputed.

Record check (judgment). Josiah and Cyrus. Most critical scholars date the first edition of Kings to Josiah's own time, in the late 7th century BC, and assign Isaiah 40 to 55 to an unnamed prophet of the exile, about 550 to 539 BC. On those readings both names were written down when the men were already known. The conservative case takes both as words spoken long before: Josephus says Cyrus himself read Isaiah's prophecy, and John 12:38–41 quotes Isaiah 53 and Isaiah 6 together and says of both, "Isaiah said these things because he saw Christ’s glory, and spoke about him." Beneath the dating sits the real question: whether God can name a king before he is born. Neither side settles that by dating alone. One more thing is plain from the text: Ezra names Jeremiah's word as fulfilled, not Isaiah's, so the Isaiah arc rests on what the two passages say, not on a stated claim.

Picture: the gold arcs, Kings and the exile. Layer: band 1.