32 If we consider closely all these mysteries of the Cross, those words of the Apostle are no longer obscure, in which he teaches the Ephesians that Christ, by His blood, made the Jews and Gentiles one "breaking down the middle wall of partition...in his flesh" by which the two peoples were divided; and that He made the Old Law void "that He might make the two in Himself into one new man," that is, the Church, and might reconcile both to God in one Body by the Cross."
Source: Mystici Corporis Christi (Vatican.va)