528 substantive letters (of roughly 2,300 that mention the redemption — most are sign-offs). The durable lever across all four decades: spread the wellsprings, for the Baal Shem Tov was told that Moshiach comes "when your wellsprings spread outward" (107 letters). The era arc: the 1940s are the wartime cry (decrees as birthpangs, immediate repentance → immediate redemption); the 1950s build out the doctrine; the 1960s turn operational; the 1970s move from personal liberation to collective redemption. The signature reversal of his own naturalism: everywhere else he says make a natural vessel; for the redemption — it comes not gradually but by a leap.
"May we merit the true and complete redemption" closes thousands of his letters. This dive isolates the letters where geulah is actually argued — where he says how it comes, when, and what we are to do about it. The center of gravity is the same lever he presses everywhere else: יפוצו מעינותיך חוצה — spread the wellsprings, and Moshiach comes.
The register moves. The war-years' most urgent slogan is retired once the war ends; the wellsprings lever endures; and by the 1970s the frame shifts from the collective to the personal-into-collective redemption.
The recurring claims about how the redemption comes, by how often each surfaces across the 528 letters.
Everywhere else he insists on a natural vessel — see a doctor, make a livelihood, trust is not passivity. Geulah is where he says the opposite: it will not come gradually, b'derech hateva, but by a sudden leap. And he refuses to let the yearning outrun the sober facts of the hour. Here, verbatim.