Bible Notes Online - Leviticus 12 - ESV
Commentary

v1-2: There were good health and hygiene reasons why the woman was "ceremonially unclean" each month. This also happened when she gave birth. This is the Lord’s words, not Moses’ opinion.

v3-5: When the baby is born, the woman is unclean for 33 days for a boy, and 66 days for a girl.

v6-7: Ritual uncleanness, as well as sins, needed atonement; this reflects God's perfect holiness.

v8: "She will be clean"; God's laws were designed to make life better, not worse; to encourage holy worship, not to be a barrier, nor to encourage guilt. This was fulfilled in Luke 2.24. Jesus Christ, in fully identifying with humanity, suffered the indignity of human birth; sacrifices were offered for Him.