Here is the text of John Henry Newman's poem, which was set to music by Elgar.
P.T. Forsyth, I think it was, who asked for it to be read to him on his deathbed. Forsyth, a Free Church theologian whose writings deeply influenced my understanding of such matters as sacraments, was not the sort of person you might expect to turn to a thoroughly Roman Catholic or mediaeval poem like Gerontius, but he did.
Elgar set about half the words, and made a good selection.
I was lucky enough to be singing in the Cambridge University Musical Society chorus when David Willcocks conducted us in this work, in King's College Chapel. That was a 'scrape me off the ceiling' experience.