The first Wesleyan Chapel in London, England, was a deserted iron foundry. It became known as the Foundry Meeting House. This hymn was written by Charles Wesley, a prolific hymnist who wrote between six to seven thousand hymns, for the first service in this chapel in 1739 just one year after his dramatic conversion experience. This hymn was originally entitled “Hymn for Easter Day” and consisted of eleven four-line stanzas. When Charles’ brother John decided to preserve the best of his brother’s hymns, this hymn and “Jesus Lover of My Soul” were left out.
The popularity of this hymn is due in part to the fine tune with which it has been wedded for many years. The composer of the music has never been identified. The joyous “alleluia” at the end of each line was not written by Wesley but was added by some editor to make the text fit the tune. “Hallelujah” or “alleluia” is from the ancient Hebrew worship service and was a common expression of praise in the early Christian Church.
Source: 101 Hymn Stories by Kenneth W. Osbeck.