Acts 15 has an interesting backstory (and textual history) that has been touched on elsewhere so here I will only say, the purpose of the section, and much of the book, is to re-envision the history of the early days of Xtianity. The deep schisms, (some might say even different origins) are made to appear superficial and inconsequential. This theme contiues with the choice of two 'prophets' from Jerusalem traveling back to Antioch to share with Paul and Barny, named Judas (yes another one) and Silas.
22 Then it seemed good to the apostles and the elders, with the whole church, to choose men from among them to send to Antioch with Paul and Barnabas—Judas called Barsabbas, and Silas, leading men among the brethren, 23 and they [l]sent this letter by them,
Shortly afterward:
33 After they had spent time there, they were sent away from the brethren in peace to those who had sent them out. 35 But Paul and Barnabas tarried in Antioch...
So Judas and Silas returned to Jerusalem. However, the narrative continues with Paul having an angry fight with Barney over Mark and so Barney takes Mark with him:
40 but Paul chose Silas, and went forth,...
So now Paul is depicted as actually sharing his missionary travels with a prophet from Jerusalem. (not in Paul's letters) But this created an obvious problem in the narrative flow as it reads today. Silas left to go back to Jerusalem and here he is still in Antioch. That brings up vs 34.
Notwithstanding it pleased Silas to abide there still.
Fact is, the problem is more complicated that it might appear at first. Without getting too mired down with comparative manuscripts, (abbreviated MSS) suffice it to say the "oldest" MSS do not have verse 34. Yet these oldest MSS are about 250-300 years separated from the writing of Acts. The reading of the verse as shown above is reflected in MSS dating back to about the 9th century. However other versions of verse 34 date back to the 5th century. Those MSS that have a verse 34 very extensively in the reading of the verse.
Codex C (5th c) reads, “Notwithstanding it pleased Silas that they should abide there still.”
Codex D (6th century) Papyrus 127 (5th c) and a number of Old Latin manuscripts (8th c) read “Notwithstanding it pleased Silas to abide there still, and Judas went on alone.”
The 14th-century John Wycliffe Bible, an “Old Latin” copy, itw (15th century) and the Clementine Vulgate manuscripts (16th) have another version, “But it was seen to Silas, to dwell there; and Judas went alone to Jerusalem.”
My point of this exercise is not due to any importance of this particular verse other than it resolves a narrative flaw. In fact, I chose this verse because it is doctrinally neutral. My point is more fundamental.
Here we have manuscript proof that even as late as the 14th century, the text was being actively altered so as to "improve" the reading. It seems at least 4 separate alterations are evident dating back to the 5th century. Most textual critics assume the various inclusions of a vs 34 was made to resolve the narrative glitch, however we really have no reason to make that assumption other than through presumption the 4th century MSS are superior. Is that a reasonable presumption?
It is logical believe that the primary restraint from altering the text was the weight of textual tradition, i.e., familiarity with the reading. It stands to reason then, the later the date the less free an editor would feel.
How should this then affect the confidence of a reader using a text largely extrapolated from MSS dating from the 4th century? Is it reasonable to believe while abundant editing and interpolation (estimated 500,000 non-spelling variations) occurred after the 4th century that no meaningful editing was done prior? Would it not rather be more reasonable to assume the greatest tendency for editing took place when the number of copies was small and those familiar with them were few?
In this example, is it possible the glitch in the narrative (assuming vs 34 is secondary) is the result of reordering the material? Was the linking of Silas with Paul a secondary thought? Is there something missing between the episodes that would explain Silas's presence? Any of these possibilities would explain the glitch.
Who knows?