I asked about this hymn a few weeks ago. @CHGiffen helpfully tracked down the melody and the history of the melody. The original melody is, as noted, from the Darmstadt Geistreiches Gesangbuch (1698), and the harmonization is from the Congregational Psalmist Hymnal, where it is listed as 88.86, turning the last four notes into two hole notes (the one "bad" thing about Musescore is that it's not really equipped to edit a hymn: I'd put all the information in its proper place, at the bottom, so if someone knows how to do so, I can correct that).

It's a sort of interesting hymn. The Latin is not especially good; the author repeats several groups of words in multiple verses, and its history is probably Protestant, or filtered through German Lutherans, although when it reappeared in the 1830s, the translator claimed that it was sourced from Thomas à Kempis, whose orthodoxy is unimpeachable, and Quesnel, who was a Jansenist.