Rom 2:29
But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
Gal 3:29
And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise.
Those passages differ somewhat.
The root of your unbelief as to this point is obvious.
You fail to understand because you reject any view that does not fit your own before finding out more about it.
If you do bother to look into a view other than your own, you again only end up revealing you do not follow core, basically generic Bible study principles, thus; the holes in your conclusions and or objections.
While, where ever we might happen to agree on any one point ends up more the result of an accidental application of right principles on your part, in contrast to its' having been the result of a conscious application of said principles on your part, that would allow you to apply them much more consistently.
Even some Mads do this.
Where their conclusions on some things make it obvious they were never properly grounded in core study principles before venturing out on their own.
From there, they conclude a thing that clearly has not followed core principles; become married to it; and forever shut off any appeal to reason they need to consider their possible violation of the core principles.
And those are some Mads.
You don't even have that much.
Ten to one you have no idea what core principles you study based on.
I challenge you to reflect on all this...
Or not...
Or continue to...dodge the truth.