The comment of the Apostle Paul that “The worker deserves his pay” appears to have been the prevailing interpretation of this verse according to the oral traditions of the Jews during the First Century and beyond.
For example, in regard to this passage from Deuteronomy, the Jewish historian Flavius Josephus wrote the following in his compendium on the history of the Jews. That is, Josephus lived during the First Century when he wrote the following.
Jewish Antiquities, Book IV, 233.
“Do not muzzle the mouths of oxen when they thresh the ears of corn on the threshing-floor, for it is not right to bar from the fruit those who joined in the work and who have exerted themselves with regard to its production. (emphasis added)
The bolded text above was not part of the Hebrew Bible, but was instead the commentary and clarification of Josephus concerning the text. That is, Josephus understood the verse to mean the ox was comparable to human beings who participate and consume from the fruit of their labors.
Several hundred years later, the Babylonian Talmud appeared, which codified the oral traditions of the Jews. The following passage reflected the same interpretation found in Josephus, but with more clarification in that the consumption of the fruit of ones labors appears only permissible for those who were “full time” employees and therefore entitled to “fringe benefits.”
Please note the areas below highlighted in yellow, and please click on the text below to view the source (online).
b. Baba Mesi'a, Folio 91B
In summary, the mention of the verses in Deuteronomy by the Apostle Paul in 1 Tim 5:17-18 appears to include the prevailing interpretation of the verse according to the oral tradition of the Jews. That is, his clarification of the verse in Deuteronomy concerning the unmuzzled ox was the prevalent Jewish interpretation of the verse at that time, which was, “The worker deserves his pay.”