The major themes as well as the significance of Pope Pius XII’s encyclical Mystici Corporis Christi

Mystici Corporis Christi is a papal encyclical issued by Pope Pius XII during World War II, on the Church as the Mystical Body of Christ. Its significance is shown the theological views which rejected two extreme views of the Church, namely rationalistic or purely sociological understanding of the Church and exclusively mystical understanding of the Church. The encyclical addresses four major themes: the origins of this doctrine; certain aspects of the Mystical Body; reasons to call the Church mystical; errors that have arisen from an incorrect understanding of this doctrine; participation of each member.

Reflecting on the origin of this doctrine, Pius XII referred to the salvation history. Man was excluded from adoption as children of God because of sin, but, through Christ, they receive the power to become sons of God. Out of his loving will, Christ established the Mystical Body so that the sacred work of redemption would endure and continue throughout the centuries, in part due to the direct participation of His Body. In addition, the doctrine is rooted in the Scripture, in the letter of Saint Paul to Colossians, and had been enforced by the teaching of Pope Leo XIII.

Regarding aspects of the Mystical Body, people through baptism are incorporated into this Body. This Body includes various states of life: clergy or laity, living a contemplative life or living in the world in their apostolates, in state of matrimony or of single. The Mystical Body includes both saints and sinners, except those in the case with much more serious matters such as schism, heresy, or apostasy. This Body is nourished and sustained by grace of sacraments and by doctrines which are important to provide the correct religious education. Pope Pius also signified that Christ, the Head, wills to be helped by His Body to carry out the work of redemption. “That is not because He is indigent and weak, but rather because He has so willed it for the greater glory of His spotless Spouse” (44).

The encyclical also provides the reason why the Body of Christ should be called mystical. It is to distinguish the Body of the Church from Christ’s physical body. Also, “this name enables us to distinguish it from any other body, whether in the physical or the moral order” (60). That is, “the Church […] as a perfect society of its kind, is not made up of merely moral and juridical elements and principles. It is far superior to all other human societies; it surpasses them as grace surpasses nature, as things immortal are above all those that perish” (63).

Then, the encyclical indicates errors that have arisen from misunderstanding of mystical body of Christ. Pope Pius criticized the error of quietism is that which “attributes the whole spiritual life of Christians and their progress in virtue exclusively to the action of the Divine Spirit, setting aside and neglecting the collaboration which is due from us” (87). He also warned the notions that underestimate the role of the frequent confession of venial sins (88), that consider private prayer with little worth (89), that our prayers should be directed not to the person of Jesus Christ, but rather to God (90). Lastly, it is significant that the encyclical pointed out the new role of the laity to encourage their active participation. Participation of each member is to strengthen and build up the Mystical Body of Christ. Participation can be expressed in different ways, such as prayer especially in the Eucharistic Sacrifice, works of Christian charity, denial of what is forbidden.