Exegesis as method of studying scripture. I see a potential…

Exegesis as method of studying scripture.

I see a potential problem with use of only exegesis in study of scriptures. And that is, it can be used to promote the view that Jewish heritage, via blood descent from Abraham and Jacob, is a prerequisite for salvation. And also promote, for those not of biological descent, coversion to Judaism as the way of salvation for Gentiles.
I can see that exegesis, nullifies the NT and christianity itself, if applied in its pure and strict form, without christian bias, to the OT.
I wonder whether Dispensationalism evolved as method to resolve this potential theological conundrum.