New Defender's Study Bible Notes
2:21 circumcising of the child. The rite of circumcision, as a sign of the Abrahamic Covenant (Genesis 17:9-14), is known also to be of significant health benefit to the male. Its performance on the “eighth day” is also now known to be the optimum time for it to be done, in terms of the most rapid recovery of the child from the operation. The coagulants in the blood of an infant normally reach their optimum effectiveness eight days after birth. Even though circumcision was only a Jewish law, the infant Jesus experienced it and thus, as our example, it is at least appropriate that Christian boys and men (whether Jews or Gentiles) likewise practice it.
2:21 named of the angel. See Matthew 1:21 and Luke 1:31.