TRADITION VS SCHOLARSHIP
The answer
Jesus, in Mark 12:17. Paul tells the Romans to pay their taxes (Romans 13:6-7), but he never quotes the saying.
Why it’s interesting
It is one of the places where a saying of Jesus would have backed Paul up. Whether he even knew it is still argued.
Genuinely debated
Learn the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.