In the same way, once we see that fulfillment of circumcision in the New Covenant is regeneration, not baptism, the consistency of the biblical revelation is seen.(source)
I have heard Dr. White make this claim repeatedly, but it seems odd to me for two reasons:
1) The claim from his Presbyterian brethren is not that baptism is the fulfillment of circumcision, but that it is the replacement. The unbloody sign of baptism replaces the bloody sign of circumcision (just as the unbloody Lord's Supper replaces the bloody Passover).
2) Regeneration is the the thing symbolized by both Circumcision and Baptism. I guess one could call it the "fulfillment" of the sign, but it is properly speaking the antitype of which both circumcision and baptism are the type. Both the type and the antitype coexisted in the Old Testament, and there was an incomplete overlap then as now. For example, Abraham believed (demonstrating regeneration) before he was circumcised, whereas we can question whether Ishmael ever believed - yet he was circumcised.
So, I find Dr. White's claim puzzling. It doesn't make sense to me to say that "fulfillment of circumcision in the New Covenant is regeneration" because on the one hand it would be more appropriate to say "fulfillment of circumcision in the Old Covenant was regeneration" or on the other hand "fulfillment of baptism in the New Covenant is regeneration."