The key phrase for Dec. 20th in the 12th C. observation, The Great “O” Antiphons, is O Radix Jesse, or Key of Jesse. It’s such a shame that the modern Church rarely uses these great teaching assets, but you can still enjoy and, hopefully, learn from them here.
Today’s hymn is Hear the Herald Voice Resounding, a Latin hymn from the 6th C. The Anglican version is Hark! A Thrilling Voice Is Sounding, an 1849 A.D. translation set to the tune Merton by W. H. Monk). It is performed by Jared Haselbarth. You can find this and other music by him at http://www.nabaudio.com.
The series was originally recorded in 2014 A.D. and revised with Jared Haselbarth’s great and uplifting solos and other modifications in 2015 A.D. This program and other resources for traditional worship are available from the Digital Library page.