Oops!...My bad. Yes there is no they there. I think I found a (they) in a version I was reading. Looking at the greek that word does not really appear. They render (autos) as (they) in the verse.
autos here does mean more or less "they." Let me explain:
Greek is like latin a number of modern romance languages (not french) in that the subject of a sentence is indicated in the verb itself. In other words, typically, one does not need to say "he said" or "they did" as two different words in these languages. The pronoun "they" or "he" is part of the verb. Blake, in his book on Case theory and systems, calls these "bound pronouns": "any kind of pronominal representation on the verb whether by forms analysable as clitic pronouns or by inflection" (Blake, Barry J.
Case 2nd ed. Cambridge: Cambridge University Press, 2001, p. 197). Now, I personally don't like this designation, because I think it fits better with languages like Hebrew.
The point, however, is that normally the greek wouldn't need "they" here to make it clear that both Paul and Barnabas were involved.
However, as I noted before, the verb
egeneto here begins a type of construction known as indirect discourse. Which means that all subsequent verbs are changed from finite verbs (i.e. the ones which give you the "pronoun" in the verb) to their infinitive equivalents (which don't).
This means that the verb "teach" isn't a 3rd person plural (they taught) but rather an infinitive (to teach). Which means that it isn't quite clear who is doing the teaching.
Now, shortly before this, the word
autous is used (acc. pl. of
autos). In this context, the accusative usually becomes what normally would be the nominative (the subject). So, the greek does say "they gathered with the church." The most likely reading afterwards IS "
they taught" but it isn't certain. It could just be barnabas. What is far LESS clear is (again) the connection of their stay and the name "christians." Again, if they author wanted to tie the various clauses together, s/he would have used another
kai. The use of
te, a far weaker connector, makes this clause an "aside" not connected with the passage in a causal or temporal sense.