Likutei Sichos – Vol 16 p 114 ff – Two Bloods (02)

Bo Exile and Redemption (111) Inside. ר’ מתיא בן חרש who lived in Rome taught that to create the nation of Yidden we must do two things: 1) Go out of evil and idolatry, through the Korban Pesach. 2) Bring good and holiness in, through ברית מילה.