God rest you merry, gentlemen; let nothing you dismayFor Jesus Christ our Savior was born on Christmas dayTo save us all from Satan's pow'r while we were gone astrayOh, tidings of comfort and joy, comfort and joyOh, tidings of comfort and joy
The phrase "To save us all from Satan's pow'r" has the same basic idea and even some of the same vocabulary as the line "'God save us from the devil' was their prayer" in "Music from the Spheres." Later in the song, "God save us from the devil" appears by itself, too.
I vaguely remembered some link between "God Rest You Merry, Gentlemen" and "Indication," but I had to do some research to find where I'd learned this. It's in Claes Johansen's Hung up on a Dream. On page 149, Argent says, "We used to do a Jimmy Reed song on stage, a blues thing called 'Baby What You Want Me To Do'. At the end of that I used to go into this long improvisation based around 'God Rest You Merry Gentlemen'! It was quite bizarre. I even used to start singing along with the improvisation. It got quite wild. We wanted to use that on a record. So that's what we did on 'Indication', with a guitar sound that was supposed to be really out in the background. It was supposed to be this thing we used to do on stage and which went down a storm." Argent quotes "God Rest You Merry, Gentlemen" in the version of "Indication" on Live at the Bloomsbury Theatre, London (starting at ~2:13) and in the live recording of "I Am the Dance of Ages" from the Paris Theatre on 14 December 1972* (at ~23:39 in the audio file).
While there is a lyrical similarity between "God Rest You Merry, Gentlemen" and "Music from the Spheres" and Argent was obviously familiar with it, it's only speculation that it was an influence here.
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*I found this concert in June 2022. The link I posted then doesn't work anymore, but the link above leads to the same recording. As I explained two years ago, I think the date given (6 January 1973) is wrong. In researching for this post, I also discovered that I had the title wrong there; it's "God Rest You Merry, Gentlemen," not "God Rest Ye Merry, Gentlemen."