Acts 17:11 These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so.<<
Now please find for us where anyone was commended for checking with anything else to see “whether those things were so” that were/are being taught. If you can't then scripture stands as the only source for the truth of what is being taught.
For a long time after Acts was written, it was not universally held to be part of the inspired Scripture. It was a final decision by the Catholic Church in Rome that definitively placed Acts in the canon of Scripture. Anyone who holds with certainty that Acts is inspired is depending on a decision by the Church in Rome.