The anthem employs antiphonic choir effects and brass fanfares. It is a setting of Psalm 122:1-3,6-7, and its title comes from the opening verse of the psalm in the Authorized Version (King James Version):
I was glad is not, however, a triumphalist piece: its focal text is the line "O pray for the peace of Jerusalem", which was fitting at a time when Britain had just suffered significant losses in the Boer War, the first major conflict the country had been involved in for nearly 50 years, and one that caused loss of life on a scale that was at the time unprecedented in living memory.