|A bris is not "shedding blood" bringing "forgiveness of sins." Not in the least. No relation to forgiving sins at all.
There is a sacrifice that had to be brought for particular sins (the korban khatat), and it was a goat.
And children don't sin. At all. (According to Jewish law, that is.) And a bris happens to an eight-day-old baby, right? No sin involved.
I'm not giving the Jewish perspective on this issue. I assumed the OP wanted the Christian perspective on circumcision, as she was reading the New Testament. Naturally the Christian view of Jewish circumcision is not the same as the Jewish view - Paul, for instance, refers to it as a mutilation (not the Jewish view), declares that it is only of value to those who keep the law (not the Jewish view), says that not all circumcised Jews are true children of Abraham (not the Jewish view), declares there is no spiritual difference in Christ between circumcised and uncircumcised believers (miles away from any
Jewish view), and so on.
That said, I wrote the above post in a hurry and wasn't very clear. I do believe the primary
purpose of circ was separation/a sign of the Covenant, and I do not believe it actually forgave sins (as my post made clear, in fact). I do believe in original sin, so I believe even infants need forgiveness/salvation. From the Christian perspective, circumcision does not impart that, but if
it is part of the process by which a baby grows up following God's law and believing God's promises - which we believe resulted in salvation for people like Abraham and Moses - it is
related to forgiveness of sins. (It ties in to the circumcision/baptism parallel in the NT, in which baptism is referred to at one point as "for the forgiveness of sins". I don't believe it means baptism actually forgives sins, as that would contradict other teachings of salvation; rather, I believe it views baptism as part of and a symbol of the salvation process. Other Christians will disagree with me on this one.) And I don't think it's a stretch to think that God chose a bloody, painful method to demonstrate the very serious and life-altering consequences of being one of God's people, and perhaps to encourage His people to look forward to a better time when it was unnecessary - as I believe it now is, under the New Covenant.