Luther was fond of this letter in his battle against the papacy because Jerome also notes the equality of bishops, as opposed to Rome claiming her bishop is superior and is so by divine right. In his preface to Jerome's letter, Luther states:
Rather, all bishops were equal among themselves. And again, the bishops themselves were the same as presbyters. Indeed [Jerome] says that the bishop of Gubbio, a small town not far from Rome, is equal to the bishop of Rome himself. Oh, how great a heretic he would be, if this holy man were alive today! It is amazing that thousands do not condemn him to the lowest hell, together with all his writings! (p. 206).Then Luther comments on the word "pope"-
And the word "pope" was the common title of bishops. Thus St. Jerome calls St. Augustine "most holy pope."* And they called Cyprian "pope in the Church of Carthage."** Hence it is evident that the entire papal hierarchy is a matter of the doctrines of men [Matt. 15:9], or, more correctly, of demons [1 Tim. 4:1], introduced through lying hypocrites. "All are equal in merit and priesthood," says Jerome. "It is the power of riches and the lowliness of poverty that make a bishop either higher or lower" (p. 206).Luther appears to be quoting the following from Jerome:
*Jerome, Epistolae 102, 103, 105, 112, 115, 134, 141 and 142 to Augustine (PL 22:830, 831, 834, 916, 935, 1161, 1179, 1180; CSEL 56:261-262, 290). In the early church "pope" was used as a title of respect that could be given to any bishop; only later did it become a title exclusive to the bishop of Rome
**For Cyprian addressed as "pope," see the letter to him from the Roman church, Epistola 30 (PL 4:303; ANF 5:308); cf. Epistola 2 (PL 4:224; ANF 5:280); Epistola 16 (PL 4:269; ANF 5:296).
It is not the case that there is one church at Rome and another in all the world beside. Gaul and Britain, Africa and Persia, India and the East worship one Christ and observe one rule of truth. If you ask for authority, the world outweighs its capital. Wherever there is a bishop, whether it be at Rome or at Engubium, whether it be at Constantinople or at Rhegium, whether it be at Alexandria or at Zoan, his dignity is one and his priesthood is one. Neither the command of wealth nor the lowliness of poverty makes him more a bishop or less a bishop. All alike are successors of the apostles.Besides this text, Luther also appealed to Jerome's Commentary on the epistle to Titus 1:5, 6, 7
Commentariorum in epistolam ad Titum), Titus 1:7 (MPL 26, 562): “The presbyter is the same as the bishop.… the bishops should have known that they were greater according to custom rather than according to the truth of the Lord’s ordinance.” Luther used this very thing in the Leipzig debate against Eck, as described by W.H.T. Dau :
[Eck's] remark that at Rome and at the Seat of Peter originated sacerdotal unity, I grant quite freely, with reference to the Western Church. But in reality the Roman Church sprang from the Church at Jerusalem, and this latter is properly the mother of all churches. But the inference which he draws is worthless: since sacerdotal unity has its origin in the Roman Church, therefore that Church is the head and first mistress over all; with his logic he might establish beyond question that Jerusalem is the head and lord over all churches. His last authority, Jerome, even if he were altogether reliable, has not been correctly quoted by our excellent Doctor; he intends to prove that the monarchical power of the Roman Church exists by divine right and has been instituted by Christ. Jerome's words do not say this. His remark: "There would be as many schisms in the Church as there are bishops, unless some extraordinary power eminent over all others were given him," means: Let us assume that this could be done by human, right, all the rest of the believers giving their consent. For I myself do not deny that if the believers throughout the world were to agree, on a first and supreme pontiff at Rome, Paris, Magdeburg, or anywhere else, this person ought to be regarded as the highest monarch out of respect for the entire Church of believers who are thus agreed. But this has never happened, nor is it happening now, nor will it ever happen; for down to our times the Greek Church has given no such consent, and yet has not been regarded as heretical. That this is Jerome's meaning I prove from his epistle to Evagrius, where he says: "Wherever there may be a bishop, whether at Rome, or Eugubium, or Constantinople, or Rhegium, or Alexandria, or Thanae, his worth and episcopal office is the same. The influence of wealth and the humiliation of poverty may make one sublime, the other lowly; nevertheless all are successors of the apostles." We find the epistle cited in Decretals that are not worthless, in the 93d distinction. In his commentary on Titus the same author says: "The presbyter is the same as the bishop, and ere by the devil's prompting there came to be competition in religious affairs and people were saying, 'I am of Paul, I of Cephas,' the churches were governed by a joint council of the presbyters. Afterwards, when each presbyter thought that those who had been baptized by him belonged to him, the rule was made for the whole circuit that one presbyter should be chosen to be above the rest." And citing Scripture-proof, he says toward the end: "Accordingly, as the presbyters knew that by a custom of the Church they were subject to the person that was placed over them, so the bishops knew that they were above the presbyters in consequence of a custom rather than of any arrangement of true overlordship." The Doctor's remark, that Jerome had referred to the Supreme Pontiff at Rome when he said: "I am speaking with the successor of the fisherman and disciple of Christ, and I am an associate of his happiness, that is, of the Seat of Peter; I know that the Church is built on that Rock," is irrelevant. It does not follow that because I associate with this particular church, therefore it is the first. It does not follow that because this church is built upon the Rock, therefore it alone is thus built up. Add to this the decree of the African council in the 99th distinction, chap. 1: "The bishop of the first seat shall not be called the prince of .priests nor the supreme priest, nor by any similar title, but only the bishop of the first seat. Nor shall the Bishop of Rome be called the universal pontiff." Now, if the monarchy of the Roman Pontiff exists by divine right, all these statements would be heresy, which it would rash to assert. To conclude, let us hear our Lord Himself, who says Luke 22: "There was also a strife among them which of them should be accounted the greatest. And He said unto them, The kings of the Gentiles exercise lordship over them; and they that exercise authority upon them are called benefactors. But ye shall not be so: but he that is greatest among you, let him be as the younger."Luther's use of Jerome would eventually find its way into the Smalcald Artilces (now part of the Book of Concord):
Consequently the church cannot be better governed and maintained than by having all of us live under one head, Christ, and by having all the bishops equal in office (however they may differ in gifts) and diligently joined together in unity of doctrine, faith, sacraments, prayer, works of love, etc. So St. Jerome writes that the priests of Alexandria governed the churches together and in common. The apostles did the same, and after them all the bishops throughout Christendom, until the pope raised his head over them all.Luther appears to be quoting from memory here, combining letter 146 and the Titus commentary.
A helpful overview of Jerome's view of th papacy was put together by William Webster The Matthew 16 Controversy (Battle Ground: Christian Resources, 1999). There, Webster begins with this statement from Jerome:
Away with all that is overweening; let the state of Roman majesty withdraw. My words are spoken to the successor of the fisherman, to the disciple of the cross. As I follow no leader save Christ, so I communicate with none but your blessedness, that is, with the chair of Peter. For this I know, is the rock on which the church is built! (p.68).One would think this quote ends all dispute as to Jerome's view (see the quote in action on the CTC blog). Webster though goes through a number of quotes from Jerome, pointing out that indeed, Jerome saw that the bishop of Rome was the successor of Peter. But, for Jerome, Christ is the ultimate foundation of the Church, and the other apostles share this with him in a secondary sense (p.69). All the apostles have the keys and equal authority. Many of the quotes from Jerome utilized by Webster are on his web page The Patristic Exegesis of the Rock of Matthew 16:18. The same Jerome letter used by Luther is also used by Webster:
When subsequently one presbyter was chosen to preside over the rest, this was done to remedy schism and to prevent each individual from rending the church of Christ by drawing it to himself. For even at Alexandria from the time of Mark the Evangelist until the episcopates of Heraclas and Dionysius the presbyters always named as bishop one of their own number chosen by themselves...For what function, excepting ordination, belongs to a bishop that does not also belong to a presbyter? It is not the case that there is one church at Rome and another in all the world beside. Gaul and Britain, Africac and Persia, India and the East all worship one Christ and observe one rule of truth. If you ask for authority, the world outweighs its capital. Wherever there is a bishop, whether it be at Rome or at Engubium, whether it be at Constantinople or at Rhegium, whether it be at Alexandria or at Zoan, his dignity is one and his priesthood is one. Neither the command of wealth nor the lowliness of poverty makes him more of a bishop or less a bishop. All alike are successors of the apostles(p.71).