18 We believe, moreover, Beloved Sons and Venerable Brethren, that to promote union and uniformity in discipline, it will be well that the Bishops of each province should often deliberate among themselves and with their Archbishop, consult about one another's interests, and, when circumstances require it, address themselves to that Apostolic See whence flow the integrity of faith, the power of discipline, and the light of truth. The numerous pilgrimages which are being projected in Spain will afford a most favourable opportunity. Nothing can, indeed, be more fit to allay dissensions and to decide controversies than the voice of him whom Our Lord Jesus Christ has constituted the Vicar of His power, and the wealth of heavenly graces which flow in streams from the tomb of the Apostles.
Source: Cum Multa (Vatican.va)