Mater et Magistra §258

Mater et Magistra: On Christianity and Social Progress

²⁵⁸ In conclusion, Venerable Brethren, We would remind you of that sublime truth of Catholic doctrine: our incorporation as living members in Christ's Mystical Body, the Church, "For as the body is one and hath many members; and all the members of the body, whereas they are many, yet are one body; so also is Christ." (60)

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Source: Mater et Magistra (Vatican.va)