Today divisions and endless theological quarrels and divisions (institutionally or in spirit) are winked at and rationalized with drivel such as "primary vs. secondary doctrines" or supposed "agreement on essentials." The first Protestants understood that schism and division was a huge scandal and cause for regret and misery. For example, Luther's right-hand man and successor, Philip Melanchthon wrote:
If my eyes were a fountain of tears, as rich as the waters of the river Elbe, I could not sufficiently express my sorrow over the divisions and distractions of Christendom.
(from: The New American Cyclopaedia, edited by George Ripley and Charles Anderson Dana, New York: D. Appleton and Co., 1861, Vol. 11, "Melanchthon," p. 361; primary source: Epistles, Book 4, epistle 100; see the same exact quote in The Unitarian Review of 1874, pp. 450-451 and American Presbyterian Review, Vol. 1, 1869, pp. 248-249; and a similar translation in The Presbyterian Review, Vol. 5, 1884, pp. 467-468)
Prominent 19th century Protestant historian Philip Schaff references this quote:
The controversies among the Protestants in the sixteenth century roused all the religious and political passions and cast a gloom over the bright picture of the Reformation. Melanchthon declared that with tears as abundant as the waters of the river Elbe he could not express his grief over the distractions of Christendom and the "fury of theologians."
(History of the Christian Church, vol. 6, p. 46)
Some secondary citations (many Catholic) show perhaps an anti-Protestant bias (only an examination of the original German -- or Latin? -- would show the most accurate version), by rendering the ending "evils of the Reformation" (Maurel), "miseries caused by the Reformation" (Barrie, Fullerton, Stoddard, Rivington), or somewhat less ostensibly polemical versions: "disasters of the reform" (Olf, Wyndham-Lewis), "miseries of the reformation" (Audin, Canfield / Hawes, Butler) "miseries of the distracted Reformation" (Spalding, Ganss, Hill / Brors, Maclaughlin, Noll, O'Hare), "divided reform" (Lovat), and "divided reformation" (Bossuet).
John Schofield, in his book, Philip Melanchthon and the English Reformation (London: Ashgate Publishing, 2006), provides the background context of a similar letter written to the English "reformer" Thomas Cranmer, c. April Fool's Day 1548:
. . . having heard of difficult negotiations over doctrine in England, he wrote to Cranmer, lamenting the plight of the church, 'buffeted as she is with divisions and strife', and lamenting that she would be buffeted still further if her leaders failed to agree. These calamities, he wrote, brought such sorrow and a 'greater flood of tears than the waters of our Elbe or your Thames', all these different theories and all this wrangling, and all the while the true teaching of the ancient church is disregarded. Philip urged Cranmer to deliberate with good and true men, and repeated what he had said in an earlier (probably lost) letter, that the church needed an inclusive, unambiguous declaration of faith and doctrine for the benefit of future generations.
I also ran across an entire English translation of this letter:
MELANCTHON TO ARCHBISHOP CRANMER
Wittenberg? About April 1, 1548.
[Printed in Melancthoni Epist., Lib. iii., Ep. 42 bis, col. 523, edit. Londini, folio, 1642. Latin.]
Translation now first published.
. . . the letter of his son Jonas arrived, in which he relates to me a certain conversation of yours, on a Question, by no means obscure, but which has severely shaken the Churches, and will shake them still more severely, because those who bear rule do not seek for true remedies in so momentous a matter.
I do not, however, desire in this letter to do any thing more than express my grief, which is so great, that it could not be exhausted, though I were to shed a flood of tears as large as our Elbe or your Thames.
You see what a multitude of explanations have been elaborated in former times, and are elaborated at this day; because a simple and sincere [appeal to] antiquity is neglected. But I omit a longer discussion at this time, not merely because the messengers are in haste, but because I do not love labyrinths; for you must be aware that it has always been my desire, on many subjects, that every thing should be completely disentangled.
I implore you to deliberate with good and truly learned men, both as to what should be determined, and as to what moderation may be expedient, in the first instance, in teaching. I could have wished, (as I wrote in a former letter,) both with regard to this question and to some other matters, that a Summary of necessary doctrine might be publicly set forth, without any private feeling; after the deliberations and decisions of pious and learned men, brought together for the discussion of those matters: so that no ambiguities should be left to posterity, as an apple of discord.
The Council of Trent makes its crafty Decrees, in order to protect its errors by ambiguous expressions. Such sophistry ought to be far away from the Church. There is not the least absurdity in true things being proposed in right words: both the goodness of the matters themselves, and their perspicuous enunciation, would invite the attention of upright minds in every part of the world.
From the very first, the Stoical disputations in our country concerning Fate, were exceedingly disgusting, and prejudicial to discipline. Wherefore, I beseech you, bend your mind to some such formula of doctrine. . . .
(George Cornelius Gorham [Anglican], Gleanings of a Few Scattered Ears During the Period of the Reformation in England [London: Bell and Daldy, 1857), pp. 42-44)
Such concerns were very common among the most important early Protestants. See:
Dialogue: John Calvin's Letter to Philip Melanchthon Concerning Protestant Divisions: Its Nature, Intent, and Larger Implications
For you see how the eyes of many are turned upon us, so that the wicked take occasion from our dissensions to speak evil, and the weak are only perplexed by our unintelligible disputations. Nor in truth, is it of little importance to prevent the suspicion of any difference having arisen between us from being handed down in any way to posterity; for it is worse than absurd that parties should be found disagreeing on the very principles, after we have been compelled to make our departure from the world.. . .And surely it is indicative of a marvellous and monstrous insensibility, that we so readily set at nought that sacred unanimity, by which we ought to be bringing back into the world the angels of heaven.
Luther's Disgust Over Rampant Protestant Sectarianism and Radical Heresies; Can't See the Connection With Sola Scriptura and Private Judgment
Was Luther in His Last Years in Agony and Bitter About the Course of Protestantism in Many Quarters (Including His Home Town)? Many Biographers Think So
Lutheran Edward Reiss Says I Can't Claim Luther Was in "Agony" Over Protestant Sectarianism, Even Though Luther Himself Said Exactly That!
1) The devil seeing that this sort of disturbance could not last, has devised a new one; and begins to rage in his members, I mean in the ungodly, through whom he makes his way in all sorts of chimerical follies and extravagant doctrines. This won't have baptism, that denies the efficacy of the Lord's supper; a third, puts a world between this and the last judgment; others teach that Jesus Christ is not God; some say this, others that; and there are almost as many sects and beliefs as there are heads.
I must cite one instance, by way of exemplification, for I have plenty to do with these sort of spirits. There is not one of them that does think himself more learned than Luther; they all try to win their spurs against me;. . .
2) Such is the blindness and presumption of these frantic heads, which even by their own judgment do condemn themselves. . . . let the minister of Christ know that so long as he teacheth Christ purely, there shall not be wanting perverse spirits, yea, even of our own, and among ourselves, which shall seek, by all means possible, to trouble the church of Christ. . . . Yea, let him rejoice in the troubles which he suffereth by these sects and seditious spirits, continually springing up one after another.
3) "In 1545, he published, in his Annotations on Genesis, and in other forms, the most bitter expressions against the Reformed, denominating Zuinglius, Oecolampadius and their adherents 'Enemies of the Sacrament,' 'Heretics,' and 'Reprobates.' Long ago, he declares, he had ceased to pray for men who were murderers of souls . . ."
(Charles Hodge, The Biblical Repertory and Princeton Review, 1839, Vol. XI, p. 358)
4) Why should I fret and fume against the papists? All they have done against me has been in fair, open war: we are declared enemies, and act as such. They who hurt me most are my own dear children. My brothers, fraterculi mei, aurei amiculi mei -- they who, if Luther had not written, would know nothing of Christ, or of the gospel, and would not have shaken off the papal yoke; for even if they had had the power to do so, the courage would have been wanting. I thought I had gone through, had exhausted all the adversities the evil one could inflict; but it was not so. My Absalom, the child of my heart, had not deserted his father, had not poured out ignominy upon David; my Judas, the terror of the disciples of Christ, the traitor who delivered up his master, had not sold me: he has done so now.