1 Timothy 5:18 Is Important In Apologetics

For example, the passage has significant implications for the canon of scripture, the dating of the Synoptics and Acts, whether Paul agreed with concepts affirmed in Luke's gospel (the virgin birth, the empty tomb, etc.), and how widely accepted the beliefs in question were (e.g., since Paul expects his audience to accept what he's saying without further explanation). And much of what I just mentioned is applicable to some extent even if Pauline authorship of 1 Timothy is rejected and the document is dated later than Paul's lifetime. For example, if the passage reflects widespread acceptance of the virgin birth, then that's significant even if Paul wasn't involved. In fact, if the initial audience was much wider than one individual (Timothy), as it presumably would be under a pseudonymous authorship scenario, then the implications of the passage are more significant accordingly.

I've sometimes cited Michael Kruger's work in support of the conclusion that 1 Timothy 5:18 is citing Luke's gospel as scripture. In a book published late last year, he provides a lengthier case for that conclusion. It's on pages 680-700 of Lois K. Fuller Dow, et al., edd., The Language And Literature Of The New Testament (Leiden, The Netherlands: Brill, 2017). If you don't want to pay the large price for the book, you can get it at a library or through interlibrary loan, as I did. Kruger's chapter is well worth getting and reading. He goes into a lot of detail, but here are some highlights:

Given that we have an exact match with a known source (Luke 10:7) - and exact matches are quite rare when tracing the words of Jesus during this time period - this raises the question of why we would prefer an unknown source to a known one. And there is another advantage of preferring the known source, namely that we know that (at some point) Luke actually acquired the scriptural status that 1 Tim 5:18 requires, whereas we have no evidence that any sayings source ever acquired such a scriptural status….

If it is too early for Luke to be regarded as Scripture, why is it not also too early for a written sayings source [a hypothetical alternative to Luke] to be regarded as Scripture? After all, one might think that Luke's purported apostolic connections (Luke 1:1-4) might allow his Gospel to be regarded as Scripture even more quickly than an anonymous sayings source….

He [John Meier, a New Testament scholar who's not a conservative and rejects Pauline authorship of 1 Timothy] states, "The only interpretation that avoids contorted intellectual acrobatics or special pleading is the plain, obvious one. [1 Timothy] is citing Luke's Gospel alongside Deuteronomy as normative Scripture for the ordering of the church's ministry." (689-91)

Kruger addresses objections to an early dating of Luke's gospel, but only briefly. For some additional evidence suggesting an early date, see here and here.