The Internet Archive has PDF scans freely available three volumes of Hermann Strack and Paul Billerbeck’s Kommentar zum Neuen Testament aus Talmud und Midrasch (München: Beck, 1922–1961):
Each of the files is reasonably large (75.7–81.5 MB). So, they may take some time to load on slower connections or browsers.
As a side note, these PDFs cover the whole New Testament. But, the SBL Handbook of Style notes a 6-volume edition of Strack and Billerbeck’s work (§6.4.7). Does anyone with better knowledge of the 6-volume version know whether (a) volumes 4–6 have contents beyond those of volumes 1–3 listed above, (b) the 6-volume version is simply a different printing of the 3-volume version, or (c) something else?
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