In Catholic apologetics I often hear that Jesus didn't condemn all traditions and, in fact, we are instructed to hold to the tradition of the Apostles (2 Thes. 2:15). However, I rarely hear in detail what the traditions the Pharisees maintained that were condemned by Jesus.
The basis of my question is that I'm in discussions with a Protestant co-worker and whenever I appeal to a OT practice as a foreshadowing of a NT belief, he responds "oh, but that was just a Rabbinical tradition". One example is the Jewish seder meal. I believe this was a common Jewish practice and Jesus would've celebrated the seder. I was describing the seder meal and explaining how that the last supper was most likely a seder. From this standpoint I tried to connect the dots from OT to NT and straight into the Eucharist. He brushed it off as a rabinical tradition which would've been condemned by Christ.
How is it that we distinguish authentic Jewish tradition from a tradition that would've been condemned?