There are some songs/hymns which are iconic in their purpose. That is, they are fairly universally-recognized for filling a certain role in the assembly. There’s “When I Survey the Wondrous Cross” for the Communion. There’s “Give Me the Bible” for a song before a sermon or about the word of God. One of the iconic praise hymns is Reginald Heber’s “Holy, Holy, Holy!” (the hymn is so iconic that it has appeared as #1 in numerous hymnals). It was written in connection with Trinity Sunday (in the liturgical year, the first Sunday after Pentecost) and the tune written for it is named NICAEA after the city where the Nicene Creed was agreed to. The Nicene Creed was the first major credal statement about the three-in-one nature of the Godhead. Revelation 4, one of the source texts, is a prescribed reading for Trinity Sunday in the Church of England’s Book of Common Prayer.