Since Acts was written at least two years after Paul arrived in Rome in chains, it would not have been ‘published’ until into the 60s. When Jerusalem was destroyed in 70, it disappeared from the Christian map for centuries—the center of gravity of the Church was now Asia Minor. Although Luke himself was no doubt very fluent in Greek, for most Christians in Asia Minor it would be a second language. If this was also true of most people who made copies of NT books (especially in the early decades), and since those books were written without punctuation (or even spaces between words), it was predictable that now and again someone would put a ‘comma’ in the wrong spot. I imagine that it would have been just such an event that gave rise to the peculiar set of variants that we encounter in Acts 12:25.

Throughout the NT there are numerous places where there is a more or less serious split within Family 35, with two competing readings (usually involving just one letter). But this is the only place (yes, only) in the whole NT where the family splinters—there are no fewer than seven variants, five of them being of some consequence.

Instead of “Barnabas and Saul returned to Antioch, having fulfilled their mission”, someone (or several someones) put the comma after ‘returned’, resulting in “Barnabas and Saul returned, having fulfilled their mission to Antioch”—but with that punctuation ‘Antioch’ must be changed to ‘Jerusalem’. (Having done that, we have two ways of saying essentially the same thing—if you get the ‘comma’ right!) Following that hypothesis, that change must have occurred rather early on, and in circumstances that resulted in that change dominating the transmission of Acts down through the years. To see what I mean we need to have the evidence before us: