In the topic most about study, the Rebbe's signature correction is “not the study but the deed is primary.” Torah must be accompanied by yiras shomayim, the fear of Heaven, or its purpose is lost; it needs fixed times, and it joins the revealed law to Chassidic teaching. Learning that does not lead to action, he writes again and again, has missed its end.
The single largest topic in the archive — and once again the 1950s hold two-thirds of it (3,352 of 5,076). Yet the most frequent counsel is not about the learning itself, but its companion (below).
The recurring calls, by how often they appear across the 5,076 letters.
The leading call is not a quantity of learning but its temper — that Torah be joined to yiras shomayim (324, and 275 of them in the 1950s).
Torah with yiras shomayim leads (324) and is overwhelmingly a 1950s theme (275) — the post-war years where he insists the learning carry awe, not only knowledge.
The call to learn both nigleh and Chassidus (102) rises into the 1960s (47) — the decade he most presses the union of revealed and inner Torah.
"Study that leads to action" climbs the other way — 7 → 21 → 16 across the 50s–70s — as the emphasis turns from building study to translating it into deeds.
In the topic most about learning, the recurring turn is away from learning as the endpoint. "Not the study is primary, but the deed" closes letter after letter (108 of them). Torah without yiras shomayim is deemed incomplete — and even the drive to print seforim is paced, not automatic. Here that reversal, verbatim.