The article linked here posits that Piper has, among whatever virtues he may have, some inclination for hymn writing. For an event for women sponsored by The Gospel Coalition (another thing I'm not keen to publicize), Piper was apparently saddled with the hymn "Great is thy faithfulness" to follow his sermon. Apparently the hymn was too Wesleyan for the über-reformed Calvinist Piper, so he decided to add a couple of verses of his own to the hymn. After all, nobody tells John Piper what to do. (You can see the added verses in the article link.)
(Personal note: that hymn was sung at my mother's funeral, primarily because as the one who had just started a church music degree at the time I was naturally asked what her favorite hymn was, and that was the one that came into my head. So now that hymn always catches my attention.)
Not surprisingly, I guess, there was a certain amount of kerfuffle over Piper seeking to bend the old hymn's theology towards his own, or something like that. You can, if you choose, finish that article for a batch of comments from varied experts of one sort or another: to me the most useful are those of Constance Cherry, of Indiana Wesleyan University. Piper's emendations don't really pass muster with Cherry's list, particularly #4 -- no one would ever think that Thomas O. Chisolm would have ever written such a thing on a poetic basis alone. For one thing, where Chisolm's text is more God-directed, Piper's is individualistic -- the pronoun "I" suddenly leaps to greater prominence than in any of Chisolm's verses (although it does appear in the refrain). The disconnect is jarring stylistically, before any theological questions even come up.
There are a lot of questions to be asked here; why would any speaker be handled a hymn to follow their sermon without any input? Why could not Piper just ask for another hymn or even write something fully new, if he's that good?
What doesn't need to be fussed over too much is the supposed unprecedented quality of such a move. It's not new. Hymns have been worked over by poetic Dr. Frankensteins before for theological and other reasons. It should be noted, though, that it's impossible for any such alteration, emendation, or augmentation of a hymn not to have theological results, and even seemingly non-theological changes to hymns are usually theological if you dig deep enough. For example, editing of hymn texts to cut gender-exclusive language for God or for humanity absolutely derive from a theological conviction: namely, that women and men are created equal in God's image, called equally by a God who we cannot confine to maleness without courting heresy. Piper himself would utterly reject such a change, but clearly isn't above such manipulation of hymn texts for theological purity.
But my main reaction, though, is that this has happened before, apparently without complaint, and to hymns far more widely popular than "Great is thy faithfulness." Indeed, possibly the most popular hymn out there for us western Christian types is a Frankenstein's hymn.
Here is the text as written by the original author:
Amazing grace, how sweet the sound that saved a wretch like me!
I once was lost, but now am found, was blind, but now I see.
'Twas grace that taught my heart to fear, and grace my fears relieved.
How precious did that grace appear the hour I first believed!
Through many dangers, toils, and snares, I have already come.
'Tis grace has brought me save thus far, and grace will lead me home.
The Lord has promised good to me; his word my hope secures.
He will my shield and portion be as long as life endures.
Yea, when this flesh and heart shall fail, and mortal life shall cease;
I shall possess, within the vail, a life of joy and peace.
The earth shall soon dissolve like snow, the sun forbear to shine;
But God, who call'd me here below, will be forever mine.
(Hat tip to Carl Daw for including those last two stanzas in the entry for the hymn in Glory to God: A Companion.)
Mostly familiar, yes? John Newton does a pretty neat trick in this text, speaking for three verses of God's past action towards us, then pivoting at the end of the third verse and looking forward to God's future provision for us for the three final stanzas (with a quick look back in the last half of the final stanza. It's pretty effective hymn writing, and remains consistently focused on God's grace to us in providing for us both in the past and in the future.
We don't get that, of course, with the emendation visited upon the hymn in our modern hymnals. I'm guessing modern hymn singers would get a bit uneasy at that final stanza's thoughts on the earth disssolving and the sun going out, not to mention the mortality of stanza five. Still, our discomfort deprives us of Newton's full message, and leaves stanza four seeming a bit abrupt and out of place for some. There is a loss here. It probably isn't enough to restore those final two stanzas, but there is a loss.
Oh, and there's that other stanza.
When we've been there ten thousand years, bright shining as the sun,
we've no less days to sing God's praise than when we'd first begun.
John Newton had nothing to do with that stanza. It first appeared in a collection called A Collection of Sacred Ballads, published in Richmond in 1790 (Newton's was first published in London eleven years before). In that collection it was the last of nine stanzas of the hymn "Jerusalem, my happy home" (or at least one version thereof). When you work your way through the nine stanzas, it actually makes sense there. It fits thematically, it fits stylistically, it just fits.
Somehow, across the nineteenth century, that stanza got detached from its original hymnic home and "floated" across texts, eventually attaching itself to "Amazing grace." It was not actually published with that hymn until 1910, but it had apparently become a common alteration to the hymn well before. It is now, of course, inseparable from the hymn, no matter how wildly different in poetic thrust or theological focus it is. I mean, who is "we"? Newton's verses have all been "me." Where is "there" based on the context of Newton's hymn as it is presented (without his last two original verses, remember)? How did we suddenly spend ten thousand years "there"? It's a stanza about the beauties of the Holy City, not about God's provision for us at all. And yet there it is stuck. It's as if Newton's original hymn was really rejected, a la Piper's disdain for "Great is thy faithfulness," and wrenched into a thing that promises us pie in the sky bye and bye instead of quietly rejoicing in God's, well, grace to us?
So, yes, "Amazing grace" is a Frankenstein's hymn, just without any one individual to whom the alteration can be attributed. Imagine if you will the mob, rather than seeking to destroy Frankenstein's monster, actually adding an arm to him. As long as "Amazing grace" remains in the general repertory of the church, complaints against modern "frankensteining" of traditional hymns, no matter how ethically sound, are going to come off as a little weak, to say the least.
Obviously even Newton's fourth stanza didn't always survive...