If you know the biblical languages, you could do a search in the the standard reference works of the respective terms in OT Hebrew and NT Greek. But if you're limited to English, then I suggest you go to Bible Gateway and do a Keyword search of the the word "Gentiles" in the NT. There you will find numerous passages where Jesus, St. Paul, and St. Peter clearly distinguish "the Gentiles" from Israel according to the flesh. When you have done this research, you will see what I mean.
Until you have done this type of study, you really don't know what you're talking about, and I don't have anything more to add. You need to do your homework before making assertions, and it's clear that you haven't done so thus far.
yvereshica adonai v'ishmareka.