Gerhardt's hymn "Of sacred head" is used in Bach's "St. Matthew Passion."
Our choir joined with others in singing it (over 3 hours) as a tribute to a much loved local musician who died in her 50s from cancer.
She suggested it for her funeral and her husband got choirs and musicians together.
The poem which Gerhardt translated from Latin to German was long attributed to Bernard of Clairvaux, though wiki now says it originated from a different 13th century source. The melody in the #3 link (and many thanks for posting 10 verses - I'd never before seen half of them) was written as a secular love song by Hans Leo Hassler, and the harmonization was done by J.S. Bach. His 5 verses used in the St. Matthew Passion grow increasingly chromatic as the story approaches the cross, to dramatize what Christ did for us. Seeing/hearing that work performed (in English) in Portland (Maine) almost 20 years ago was an incredibly moving experience.