Ecclesia de Eucharistia §35

³⁵ The celebration of the Eucharist, however, cannot be the starting-point for communion; it presupposes that communion already exists, a communion which it seeks to consolidate and bring to perfection. The sacrament is an expression of this bond of communion both in its invisible dimension, which, in Christ and through the working of the Holy Spirit, unites us to the Father and among ourselves, and in its visible dimension, which entails communion in the teaching of the Apostles, in the sacraments and in the Church's hierarchical order. The profound relationship between the invisible and the visible elements of ecclesial communion is constitutive of the Church as the sacrament of salvation. Only in this context can there be a legitimate celebration of the Eucharist and true participation in it. Consequently it is an intrinsic requirement of the Eucharist that it should be celebrated in communion, and specifically maintaining the various bonds of that communion intact.