Don't you love it when you are learning a new hymn, only to find it is set to a tune you already know?
This happened to me while learning to sing “When Love is Found,” which is set to the tune “The Water is Wide,” a song I have sung often and studied in voice lessons.
This hymn can be thought of as a matrimonial hymn for longtime spouses, as it begins with “When love is found, and hope comes home, sing and be glad that two are one.” I also vaguely feel that this tune would work well on bagpipes, as it has such a wistful sound. Indeed, I later discovered that this song seems to have Scottish origins dating back to the 1600's!
Folk singer Pete Seeger covered this song on a guitar with a choir, and gave it a whole new communal feeling for me. You might want to look up the cover just for your own musical edification.