Epistles
Paul's Epistles to the Galatians, Philippians, and Philemon are exactly what they say they are—epistles. That's just a fancy word meaning letters. Translation: we're sorting through some of Paul's really old mail. Though Paul probably wrote lots more letters to the Christians in these communities, these three are all we have left. What can we say; parchment doesn't age well.
Because these are letters, that means they were written to specific people at specific times. It'd be kind of like if someone took a handful of text messages you wrote last week and tried to pull some kind of extraordinary meaning out of them 2,000 years later. Maybe you were feeling kind of goofy when you texted "Ermahgerd!" to your bestie. But now, future people are bowing down to worship their new deity, Gerd.
In Galatians, Paul criticizes Jewish law pretty harshly. But later, in Romans, he has some kinder words for the Torah. Does that mean there are other things Paul would change in these letters? Passages he would take back? If Paul knew his thoughts would form the basis of Christian thought for centuries to come, would he have at least run these through spell check?