So, I undertook surgery on the cassette tape that contained the song. I managed to crack the commercial cassette case and extract the tape. Fixed the broken splice with good ol' Scotch tape. Then I took a blank cassette tape with the cheap case you can unscrew, removed its blank tape and put the jury-rigged tape into it. Carefully rewound it. Put in my car tape player, and -- VOILA! It sounded great.
So, I managed to refresh my acquaintance with the song and jot down the lyrics. Then I hacked out the chords alternatively on piano and guitar. It's ready for use as the finish for my sermon on Sunday, if I go the full performance route.
My trusty miniature Swiss army knife plus a Phillips screwdriver meant for work on eyeglasses was all it took. Some days, that's enough.