Why are there no last names in the bible?

Answer 1

Most people in those days did not have surnames as we think of them. The only Mary in the Gospels with a "last name" was Mary Magdalene, or Mary the Magdalene, a.k.a. Mary of Magdala, a town on the western shore of the Sea of Galilee. The significance of Iscariot is in question, but most scholars agree that it is a descriptive term, not so much a family name or surname as we now consider them. A similar example is Simon Barjona, mentioned in Matthew 16:13-18 in the King James Version. "Barjona," or Bar-Jonah, is simply a Hebrew term meaning "son of Jonah," "son of Jonas" (a more Grecian form), or "son of John" (Latin/Roman). Consider that many existing surnames came from descriptions. "Johnson," for example, probably referred to the son of John. "Sewell" may have come from a reference to a sea well or sea wall. Other surnames may not have clear English meanings, but they do or did in other languages or older dialects of languages.

Answer 2

Generally, this was just the habit of the day, although there are often early signs of such being introduced to differentiate people of the same first name such as James and John sons of Zebedee. This would thus distinguish them from other James's and John's. Jesus also had two Judas's as his disciples and they are given additional titles to distinguish them, Judas Iscariot and Judas the brother of James. The two Simons are also distinguished since Jesus gave Simon the surname (what we would call a last name) and similarly Simon Zelotes (probably not a last name but indicating he was a Jewish zealot or had leanings that way). These two examples are in the verses below:

14Simon, (whom he also named Peter,) and Andrew his brother, James and John, Philip and Bartholomew, 15Matthew and Thomas, James the son of Alphaeus, and Simon called Zelotes,16And Judas the brother of James, and Judas Iscariot, which also was the traitor.