23 As a matter of fact, We behold these priests standing shoulder to shoulder, obedient and respectful to the commands of their prelates despite the fact that to obey means in the majority of cases serious dangers for themselves, for they must live from their holy office, and since they are poor and do not themselves possess anything and the Church cannot support them, they are obliged to live bravely in poverty and in misery; they must say Mass in private; they must do all within their power to provide for the spiritual needs of their flocks, to keep alive and increase the flame of piety in those round about them; moreover, by their example, counsels and exhortations, they must lift the thoughts of their fellow citizens to the highest ideals and strengthen their wills so that they, too, will persevere in their passive resistance. Is it any wonder, then, that the wrath and blind hatred of our enemies are directed principally and before all else against the priesthood? The clergy, on their side, have not hesitated to go to prison when ordered, and even to face death itself with serenity and courage. We have heard recently of something which surpasses anything as yet perpetrated under the guise of these wicked laws, and which, as a matter of fact, sounds the very depths of wickedness, for We have learned that certain priests were suddenly set upon while celebrating Mass in their own homes or in the homes of friends, that the Blessed Eucharist was outraged in the basest manner, and the priests themselves carried off to prison.
Source: Iniquis Afflictisque (Vatican.va)