For what concerns diversity of rites in the sacred liturgy, the Apostolic See has always made its position clear: not only it does not condemn diversity, but it eagerly and willingly grants to each nation the right to keep and preserve the legitimate customs and traditions of its forbears.
Pope Leo XIIIThey knew only too well the intimate bond which unites faith with worship, 'the law of belief with the law of prayer,' and so, under the pretext of restoring it to its primitive form, they corrupted the order of the liturgy in many respects to adapt it to the errors of the Innovators.
Pope Leo XIIINothing emboldens the wicked so greatly as the lack of courage on the part of the good.
Pope Leo XIIIThese most crafty enemies [the devils] have filled and inebriated with gall and bitterness the Church, the spouse of the Immaculate Lamb, and have laid impious hands on Her most sacred possessions. In the Holy Place itself, where has been set up the See of the most holy Peter and the Chair of Truth for the light of the world, they have raised the throne of their abominable impiety, with the iniquitous design that when the Pastor has been struck, the sheep may be scattered.
Pope Leo XIIIThoughtful men, with hearts craving the truth, have come to seek in the Catholic Church the road which leads with surety to eternal life. They have understood that they could not cleave to Jesus Christ as the Head of the Church if they did not belong to the Body of Jesus Christ which is the Church. Nor could they ever hope to possess in all its purity the faith of Jesus Christ if they were to reject its legitimate teaching authority entrusted to Peter and his successors.
Pope Leo XIII