These are my Bible study notes on the topic of circumcision.
Circumcision began with Abraham as a physical act, and continued for the nation of Israel. But even in the Pentateuch, the first five books of the Bible, there are numerous indications that circumcision was symbolic of a spiritual state. The Israelites were exhorted to be "circumcised in heart".
In the New Testament, the spiritual symbolism of circumcision is emphasised, and transcends the physical. Circumcision was an important and contentious doctrinal issue in the early New Testament church, as the early Jewish Christians contended with the question of how non-Jewish (or non-Israelite) people could come to salvation through Jesus Christ.