In the Bull Exsurge Domine Pope Leo X condemned the positions of Martin Luther and others:

For we can scarcely express, from distress and grief of mind, what has reached our ears for some time by the report of reliable men and general rumor; alas, we have even seen with our eyes and read the many diverse errors. Some of these have already been condemned by councils and the constitutions of our predecessors, and expressly contain even the heresy of the Greeks and Bohemians. Other errors are either heretical, false, scandalous, or offensive to pious ears, as seductive of simple minds, originating with false exponents of the faith who in their proud curiosity yearn for the world’s glory, and contrary to the Apostle’s teaching, wish to be wiser than they should be. Their talkativeness, unsupported by the authority of the Scriptures, as Jerome says, would not win credence unless they appeared to support their perverse doctrine even with divine testimonies however badly interpreted. From their sight fear of God has now passed.

After the list of condemned positions, he says:

No one of sound mind is ignorant how destructive, pernicious, scandalous, and seductive to pious and simple minds these various errors are, how opposed they are to all charity and reverence for the holy Roman Church who is the mother of all the faithful and teacher of the faith; how destructive they are of the vigor of ecclesiastical discipline, namely obedience. This virtue is the font and origin of all virtues and without it anyone is readily convicted of being unfaithful.

Therefore we, in this above enumeration, important as it is, wish to proceed with great care as is proper, and to cut off the advance of this plague and cancerous disease so it will not spread any further in the Lord’s field as harmful thornbushes. We have therefore held a careful inquiry, scrutiny, discussion, strict examination, and mature deliberation with each of the brothers, the eminent cardinals of the holy Roman Church, as well as the priors and ministers general of the religious orders, besides many other professors and masters skilled in sacred theology and in civil and canon law. We have found that these errors or theses are not Catholic, as mentioned above, and are not to be taught, as such; but rather are against the doctrine and tradition of the Catholic Church, and against the true interpretation of the sacred Scriptures received from the Church. Now Augustine maintained that her authority had to be accepted so completely that he stated he would not have believed the Gospel unless the authority of the Catholic Church had vouched for it. For, according to these errors, or any one or several of them, it clearly follows that the Church which is guided by the Holy Spirit is in error and has always erred. This is against what Christ at his ascension promised to his disciples (as is read in the holy Gospel of Matthew): “I will be with you to the consummation of the world”; it is against the determinations of the holy Fathers, or the express ordinances and canons of the councils and the supreme pontiffs. Failure to comply with these canons, according to the testimony of Cyprian, will be the fuel and cause of all heresy and schism.

With the advice and consent of these our venerable brothers, with mature deliberation on each and every one of the above theses, and by the authority of almighty God, the blessed Apostles Peter and Paul, and our own authority, we condemn, reprobate, and reject completely each of these theses or errors as either heretical, scandalous, false, offensive to pious ears or seductive of simple minds, and against Catholic truth.

The list of condemned positions contains this: “33. That heretics be burned is against the will of the Spirit.”

Several things should be noted about this. In one way, the Catholic understanding is that the will of God is always fulfilled, and in this sense one would say that if a heretic was burned in fact, then it must have been the will of God. But the proposition is not about the will of God in this sense. The proposition in question is basically that it is wrong to burn heretics, and Leo X intended to condemn this proposition.

Second, the condemnation does not say which labels apply to which propositions, and some of the labels do not absolutely imply that a statement is false. A statement could be scandalous, offensive to pious ears, and seductive of simple minds, but still be true. In such a case the prohibition would be for the sake of practical motives, much as we suggested was mostly the case of the early opinions of the Pontifical Biblical Commission.

The Pope also says, “For, according to these errors, or any one or several of them, it clearly follows that the Church which is guided by the Holy Spirit is in error and has always erred.” If one takes this statement strictly, together with what follows, he would be asserting that it is completely necessary to hold the opposite of each of the condemned statements, or else to abandon the Church. However, there is some tension here with the previous fact about the labels; if he meant this strictly, then he could have condemned them all as heretical or as implying heresy, but he did not. In this sense, it is probably not necessary to interpret this statement as committing the Church absolutely to the statement that it is moral to burn heretics. Nonetheless, the condemnation strongly suggests that Pope Leo X both believed this and wanted others to believe it.