This is one of the most ancient hymns of the Church to remain in constant use. It is the only hymn printed in The Book of Common Prayer, where it is set for use at the Ordination of Priests and the Consecration of Bishops. John Cosin, one of the architects of The Book of Common Prayer (1662) gave us a very compressed version of the original six verses, in which each verse and each line deserves notice. It is a prayer for the gift of the Spirit in his completeness, seven being the Jewish number of perfection. The Holy Spirit in many ways has been the least thought-of member of the Holy Trinity, but the reason for that is provided in verse 4 where it is acknowledged that the chief work of the Spirit is to lead us to the Father and the Son.
The tune is probably older than the words, being associated with a hymn from the school of St Ambrose. It is usually sung in this rather simplified form, which suits congregations accustomed to a rather different kind of hymn tune.
from notes by Alan Luff © 2002