The censer swings, and an unmistakable aroma fills the church. For some, it brings back fond memories from childhood; others shift uncomfortably and wonder why we use incense in Masses at all. Incense has a long history of use in religious ritual, but the Catholic Church has refined it with additional meanings from our tradition.
Incense is made from tree resin; that is, the dried sap of certain trees is collected, and when burnt, it creates a pleasing aroma. These resins are generally combined with other substances, such as herbs, to generate a particular smell or to slow the burning. In the ancient world, incense was known from Egypt to Japan, and its purpose could be religious or merely practical. After all, the ancients had fewer options than we do to banish unwelcome odors.
In the Judaeo-Christian tradition, its significance comes from two of its aspects: cleansing fire and rising smoke. The former suggests purity, and the latter represents prayer. Already in the Old Testament, extensive instructions for the use of incense can be found in Exodus Chapter 30, while Psalm 141 makes explicit the connection between incense smoke and prayer (verse 2).
Christianity carried over much from the Jewish tradition, but added its own ideas as well. Frankincense was one of the gifts brought by the Magi; while the gold marked Christ as King and the myrrh foretold His death, the frankincense spoke to His Divinity. Incense also figures prominently in Revelations 8:3-5, explicitly merging the prayers of the Church with the worship made by the angel in those verses.
These factors explain the significance of incense in general, but there are often additional meanings behind the way it is used in specific contexts. The censer will often be swung in multiples of three to give honor to the Trinity. Moreover, incense can be used for specific purposes; as Fr. Julian von Duerbeck at St. Procopius Abbey observes, the censer is swung around the altar before Mass to mark out sacred space within a space that is already sacred, while its use in a procession evokes the pillar of fire that preceded the Israelites in Exodus.
Incense is classified as a sacramental, and a deeper investigation of its use will reveal many more meanings, such as the offering of something expensive to glorify God.