Who Were Mark and Luke?

To add to what others have said:

The early manuscripts consistently say just that the authors were "Mark" and "Luke" without further qualification. Papias (in an excerpt quoted by Eusebius) discusses Mark's role in recording Peter's preaching in the Gospel, but says nothing further about who this Mark was. Irenaeus clearly identifies Luke as the companion whom Paul repeatedly mentions. As likely as this seems, it is at least possible that this was an assumption based on a coincidence of names.

The case of "Mark" is especially tricky, since the name was so common. On the one hand, Acts mentions a "John, whose other name was Mark". On the other hand, Paul mentions "Barnabas's cousin Mark". There could be one Mark or two or three, but there is little strong evidence in either direction. Interestingly, the early Church Fathers do not identify Mark the Evangelist with the other Marks. Identification with the Mark mentioned by Paul occurs first in the Adamantius Dialogue, probably as a tendentious assumption, and next in Jerome, as explicit speculation. Identification with John Mark arises later still.

The ancient sources are divided as to how Mark and Luke relate to Jesus. The excerpt of Papias (ca. 100) mentions that Mark never saw Jesus in the flesh, and the Muratorian Fragment and Chromatius (both probably ultimately following Papias) say the same of Luke additionally. On the other hand, over two centuries after Papias, both the Adamantius Dialogue and Epiphanius (as well as the later list of pseudo-Hippolytus) count both Mark and Luke among Jesus's seventy-two disciples. At least for the Adamantius Dialogue, it seems to be a tendentious assumption, as the protagonist acknowledges his opponent's point that they were not among the Twelve, but salvages their credibility by counting them among the unnamed seventy-two, apparently unaware of Papias's contradictory information.

To follow Papias, Mark did not know Jesus at first hand but recorded the preaching of Peter, who did. Presumably Luke compiled his information from the various eyewitnesses (including, many think, Mary) mentioned in his prologue.

From the second century, Mark and Luke came to be seen as the probable authors of two of the New Testament gospels, as were Matthew and John. The fourth century Church historian Eusebius, in Ecclesiastical History,III, credits Papias, a bishop from the early second century, with naming Mark as a Gospel writer:

Ecclesiastical History,III, 39.15: Mark became Peter's interpreter and wrote accurately all that he remembered, not, indeed, in order, of the things said or done by the Lord. For he had not heard the Lord, nor had he followed him, but later on, as I said, he followed Peter, who used to give teaching as necessity demanded but not making as it were, an arrangement of the Lord's oracles, so that Mark did nothing wrong in thus writing down single points as he remembered them. For to one thing he gave attention, to leave out nothing of what he had heard and to make no false statements in them.

Since Eusebius was a sometimes unreliable historian, we can not be certain whether Eusebius is reliable in attributing to Papias the claim that Mark was a gospel author, and Rex Wyler point out, in The Jesus Sayings, page 119, we possess no other evidence that supports this conjecture. The Mark to whom Eusebius refers had been mentioned by Paul as one of his fellow workers in his Epistle to Philemon (chapter 24) and also mentioned in Acts of the Apostles. Then, in the first epistle of Peter (l Peter 5:13), a pseudonymous document from the late first century or early second century, Mark is mentioned as Peter's son. It is on the basis of these reports that Papias is likely to have seen Mark as a possible gospel author.

Raymond E. Brown says in An Introduction to the New Testament, page 267, that by the latter half of the second century, the gospel now known as Luke was being attributed to Luke the companion whom Paul mentions in Philemon 24, and who is also mentioned under Paul's name in Colossians 4:14 and 2 Timothy 4:11.

Bart D. Ehrman says in Forged, page 207, Luke was established as the author of the gospel that now bears his name, and therefore of Acts, by a process of elimination. The anonymous author was someone who especially concerned with the Gentile mission of the early church and who is particularly interested in showing that Gentiles do not have to become Jews in order to be Christian, so it is sensible to conclude that this person was probably himself a Gentile. By his occasional use of “we”, the author is claiming to be a travelling companion of Paul.

There are three persons in Colossians who were Gentile companions of Paul: Epaphras, Demas, and Luke. Of these, Ehrman says it seems unlikely that Demas could be the author, since we learn elsewhere that Demas "abandoned" Paul (2 Timothy 4:10). Epaphras appears to have been known as the founder of the church in Colossae (Colossians 1:5-7), a church that is never mentioned in Acts, so it would be odd if its founder were the author. This leaves one candidate as the author of Luke and Acts of the Apostles: Luke the Gentile physician.

Luke 10:1 (NIV)

After this the Lord appointed seventy-two^[a] others and sent them two by two ahead of him to every town and place where he was about to go.

_{[a] Some manuscripts seventy; also in verse 17}

Jesus did not have only Twelve disciples. There were other Seventy or Seventy-two disciples that Jesus appointed to preach the Gospel.

According to Wikipedia, it is possible that Mark and Luke were included in the Seventy disciples (check the list of Seventy disciples). If this is the case, it is no wonder that Mark and Luke could write the Story of Jesus accurately.