Well having been whacked when I was 8 days old in New Mexico I will answer the following.....
1. Circumcision was in the O.T. the OUTWARD sing of the INWARD covenant between God and Abraham/Abraham's SEED I.E. the lineage of faith......It did not save them, but rather (separated) them from those around them who were not participants in the covenant of faith.
2. Under the New Covenant baptism is now the outward sign of the inward covenant as applied unto believers and states to the world that you have died with Christ, been buried with Christ and resurrected in Christ as a new creation in Christ Jesus....
Does not Paul cover this in Galatians and other books as well in various form or fashion......So......seems to me that Baptism has overtaken circumcision as the OUTWARD sign of an inward act of faith.......
Anyway, fully expect the LAWyers to argue.........!