Jesus was not teaching “Christians”, was he? He was sent “only to the lost sheep of the nation of Israel” (Matthew 15:24). It was Paul whom Jesus called to go to the Gentiles, remember? We were “without hope and without God in the world” before that.
If you listen to the one Jesus sent for you, there is no opposition because you aren’t trying to steal stuff from Israel things but instead getting the things He has for YOU.
These things are heavenly, spiritual and not earthbound. Like I said, Paul will blow up your Labyrinth REAL good. This is why you find Catholics ignoring him in favor of Jesus speaking to THE JEWS, and then trying to put teaching given to those UNDER THE LAW on Gentile, post-Resurrection believers who are NOT UNDER LAW BUT UNDER GRACE.
It doesn’t work...without the smoke, mirrors and sticky tape of Rome.
"Christians" -- followers of Christ -- do not consider his teachings something to be ignored. Otherwise, we'd be called "Paulians".
He was sent “only to the lost sheep of the nation of Israel”
There isn't one Gospel for Jews and another Gospel for Gentiles -- Paul himself makes this crystal clear in Romans! -- so the Gospel Jesus preached is just as valid for Gentiles as it is for Jews, even though he left the evangelization of the Gentiles to others.
post-Resurrection believers who are NOT UNDER LAW BUT UNDER GRACE
You really have to misread Romans to not understand that EVERYONE IS UNDER GRACE, AND ALWAYS HAVE BEEN, no matter what the Pharisees and Judaizers preached.