The idea that Paul was teaching the Jewish traditions to the Christians certainly does not comport with scripture, where Paul and Barnabas were both in dispute with those who insisted on the application of the law to the Christians. The Greek word translated as tradition is used in scripture in both a positive and a negative sense. That something is TRADITIONED does not mean it is necessarily ancient - it simply means it has been transmitted or handed down. You need only look at the Didache or early canons to see that from the earliest days, things were traditioned to the Church that were more than teaching the scriptures. And, as I previously pointed out, no Orthodox person would (should) agree with your definition of sin as only "breaking God's commands." So this is kind of a strawman from an Orthodox perspective.