Unlike the writings of the apostle Paul, the books of Luke and Acts do not record the author’s name. So how do we know who really wrote them? Despite not having a convenient title page with a copyright date and the writer’s name, there are several reasons to be confident that Luke wrote the gospel that bears his name.
When looking at the evidence for Lukan authorship of the book of Acts it is important to understand that the author of Luke also wrote the book of Acts. Both books are addressed to Theophilus (Luke 1:3, Acts 1:1), and Acts begins by mentioning a “former book” which is very likely a reference to the Gospel of Luke. As we have mentioned before, the books of Luke and Acts are a single work, often referred to as Luke-Acts. Keeping this in mind helps us to accurately frame the discussion of authorship.
Although Luke-Acts is technically anonymous, there are several indications within the text to support the tradition that Luke is the author. Among the more helpful data found in the text is that the author was not an apostle (Acts 1:2), but he was present at many of the events he narrates (1:1). Examining the language of the text also indicates that the author was well educated, familiar with writing polished Greek, and had an excellent understanding of the politics and culture in this region during the first-century. This information matches what we know about Luke and helps cement the traditional position of Lukan authorship.
Several times the author switches from writing in the third person to using ‘we.’ This implies that he was present at several of the specific events being described (Acts 16:10–17, 20:5–15, 21:1–18, and 27:1–28:16). These passages are very important in discerning the most likely author of this work, as the ‘we’ is often in reference to the author and Paul being companions. From this we can deduce that Paul would likely make reference to this person in his epistles.
While Paul mentions several men, Aristarchus, Tychicus, Timothy, and Mark are mentioned in the third person within the text and so are ruled out as candidates for authorship of Acts. Of the remaining possibilities, the consensus of early Christian tradition points to Luke as the author of Luke-Acts. This is what was passed on by Irenaeus and Tertullian, and the earliest manuscript of this gospel has the inscription “According to Luke.” There are no early Christian traditions that attribute this gospel to anyone other than Luke.
Even though we aren’t told within the text that Luke wrote Acts and the Gospel that is attributed to him there is ample evidence that he is in fact the author. Having established authorship, we can move on to a related question: when was the book of Acts written (and why does that matter)?