17 What a spectacle for heaven and earth is not the Church in prayer! For centuries without interruption, from midnight to midnight, is repeated on earth the divine psalmody of the inspired canticles; there is no hour of the day that is not hallowed by its special liturgy; there is no stage of life that has not its part in the thanksgiving, praise, supplication and reparation in common use by the mystical body of Christ, which is the Church. Thus prayer of itself assures the presence of God among men, according to the promise of the divine Redeemer: "Where there are two or three gathered together in my Name, there am I in the midst of them" ( Matth . xviii. 20).
Source: Caritate Christi Compulsi (Vatican.va)