The old testament justifies the “new”. Also, the character of Jesus says that “not one jot or tittle” thing.

I was raised with red letter xtianity; but if you really do look closer, it’s easy to see that xtianity is truly a Rorschach’s blot, and for good reason. You can cherry-pick extreme right, white nationalist stuff out of there, or you could just still to the red letters and be radically leftist.