Who gave a reason for the purging of evil for the Blessed Virgin and her first child ?
Beginning with St. Gregory Nazianzen, his explanation of the "purification" of Jesus and Mary at the circumcision (Luke 2:22) prompted him to consider the primary meaning of "purification" in Christology (and by extension in Mariology) to refer to a perfectly sinless nature that manifested itself in glory in a moment of grace (e.g., Jesus at his Baptism).