We are joyful when We learn from you in your communications that those in charge of souls diligently fulfill the obligation of their office on Sundays and other holy days of obligation, on which they rarely omit to offer the sacrifice of the Mass for the people entrusted to them. But we are not ignorant of the fact that in many places the Mass is now customarily omitted by pastors on those other days which were formerly kept as holy days of obligation according to the constitution of Our Predecessor Urban VIII. Agreeing to petitions of various holy bishops and having before his eyes their causes and reasons, He lessened the holy days of obligation and not only permitted people to perform servile work, but granted also that they be exempt from the obligation of attending holy Mass. But where this generous indult of the Holy See was promulgated, straight-away the pastors of many regions, considering that they were free from the obligation of celebrating Mass for their people on these reduced holy days, neglected the obligation altogether. Hence the custom evolved that pastors in these regions stopped offering holy Mass for their people on the said days, and some did not even hesitate to defend and justify this custom.
We are greatly grieved by this situation; therefore, We have decided to remedy this matter especially since We are aware that this Apostolic See has taught that pastors are obliged to celebrate Mass for their people even on the reduced holy days. Our Predecessors were moved by the vigorous pleas of holy bishops; and many and varied needs of the faithful; and the grave concerns of circumstances, times, and places. As a result, they decided to lessen the number of holy days of obligation, and allowed people to undertake servile work on these days and to miss Mass. Nevertheless these same Predecessors, in granting these indults, wished that the law remain intact and inviolate. They wished that on the aforesaid days no innovation ever be made in the churches as to the customary order and rite of the divine offices. They meant for all things to be carried out the exact way they were before, while the constitution of Urban VIII was in force. This prescribed the holy days of obligation. On those days pastors are not free from the obligation of offering Mass for their people; they will realize this, especially when they recall that the pontifical rescripts are to be strictly interpreted. Moreover, We have frequently decreed, that pastors are bound by the obligation of saying Mass for their people even on those days which were removed from the number of holy days of obligation.
Wherefore, having weighed this matter carefully and having consulted certain Cardinals of Our Congregation for the Preservation and Interpretation of the Decrees of the Council of Trent, We have decided to write this encyclical letter to establish norm and law to be observed carefully and diligently by all pastors. Accordingly in this letter We declare that pastors and all those actually having care of souls should celebrate holy Mass for their people on all Sundays and on days of obligation. Mass must also be offered on those days, which by indult of this Holy See were removed or transferred from the number of holy days of obligation, just as the clergy were obliged to do when the constitution of Urban VIII was in full force before holy days of obligation were lessened or transferred. As for feasts which have been transferred we make one exception, namely when the divine office of a solemnity has been moved to a Sunday, only one Sunday Mass need be offered by pastors for their people, since the Mass, being the principal part of the divine office, is considered as transferred along with the same office. — from Amantissimi Redemptoris (1857)
