74 How is this relationship between the Holy Mass and the Church brought about? The Eucharist contains the entire spiritual riches of the Church since the Church has no other spiritual riches apart from Jesus Christ and that which was given to her by Him. The Eucharist builds up the Church, constitutes the Church, in the sense that the Eucharist unifies it, nourishes it, and makes it grow as an authentic communion of God’s people in its rich diversity and in its deep unity. The Church lives from the Eucharist. The entire life, word and structure of the Church, is essentially Eucharistic. The Eucharist is the source and the high point of its spiritual life, its holiness and the witness of the faithful. The same Eucharistic Bread, made from many grains of wheat, and the wine, made from many single grapes, together signify the unity and diversity of the Christian people who celebrate the Eucharist. At the same time, the Church brings about the Eucharist, that is to say, it celebrates it and offers it to the Father, united to Christ in the Holy Spirit. 245