Growing side by side with the world-wide movement of Catholic Action there is the ever-spreading liturgical revival. They are but two aspects of the one fact—the mutual co-operation of the faithful among themselves and with their pastors; and they differ in that Catholic Action, of its very nature, includes the liturgical movement. Catholic Action includes corporate activity both ad intra and ad extra: the sanctification of individuals and the defence and advance of Christianity in a semi-pagan world.

To push on the external manifestation of Catholic Action without paying due attention to the preliminary of personal sanctity is to make bricks without straw: Nisi Dominus aedificaverit domum, in vanum laboraverunt qui aedificant earn. Furthermore, the interior life must be looked to, to provide inspiration and strength as the cause progresses. There is one outstanding practice of the faithful which gives them a perennial ‘unity without uniformity,’ namely the fundamental act of public external worship of God, as expressed in the sacrifice of the Mass. For, as Fr. Pepler puts it: ‘when we speak of the liturgy, we mean primarily the Mass; and the Mass becomes the essential link of Christian unity.’ ‘Attendance at this ceremony has been imposed as an obligation of membership, so that theoretically the whole Catholic world is present at least once a week. This is the main symbol of the catholicity of the Church.’

The Pope has urged time and again that Catholic Action is an apostolate. It procures not only the personal sanctification of him who participates in it (although this is the foundation), but that also of others.