Yes, Paul tells us we need not be circumcised to be saved, and he was right.
Uh, much more than that. To a first century Jew keeping the Law was hundreds of commandments, not just circumcision. Plus, it included hundreds upon hundreds of 'traditions' which Christ rebuked over and over (start with Matthew 23 & 24). This is akin to Roman Catholic sacraments and traditions.
Furthermore the idea that its Christ + sacraments, or Christ + tradition, or Christ + Roman Catholicism is more blasphemy. It slaps Christ in the face and tells Him, "I'm sorry but your suffering and death wasn't enough for me...I need to add to it." You go ahead and do that and hope it works out for you.
When He asks me why He should let me into His Heaven, all I'm going to do is point to the cross and say "It was finished" and throw myself on His mercy.