18 It is therefore, a pleasure for us, a full century having passed since the Pontiff of immortal memory, Pius IX, solemnly proclaimed this singular privilege of the Virgin Mother of God, to summarize the whole doctrinal position and conclude in these words of the same Pontiff, asserting that this doctrine "vouched for in Sacred Scripture according to the interpretation of the Fathers, is handed down by them in so many of their important writings, is expressed and celebrated in so many illustrious monuments of renowned antiquity, and proposed and confirmed by the greatest and highest decision of the Church" (Bull Ineffabilis Deus ), so that to pastors and faithful there is nothing "more sweet, nothing dearer than to honour, venerate, invoke and praise with ardent affection the Mother of God conceived without stain of original sin. ( Ibidem .)
Source: Fulgens Corona (Vatican.va)