The Lavabo and Incensation
The lavabo, the washing of the priest’s hands (lavabo in Latin translates into English as I shall wash) usually follows, though this is another point in the Mass where incense may be used.
Let’s look at the optional action first, since it would come before the lavabo, which will happen at every Mass, weekend or weekday.
After the prayer, the server brings the thurible and the boat with incense to the priest. With the assistance of the deacon, the priest adds some incense to the thurible, blesses it in silence with the Sign of the Cross, and incenses the gifts, the altar, and the cross. This is meant to signify the Church’s offering and prayer rising like incense in the sight of God.
When the priest has completed this action, he hands the thurible to the deacon, or to the server if the deacon is absent. The deacon (or server) bows to the priest-celebrant, incenses him, and then bows again. This series of actions is repeated for the concelebrating priests, other deacon present, and the people. The GIRM tells us this is done for the clergy because of their sacred ministry, and for the people, by reason of their baptismal dignity. The incense draws the community gathered, clergy and lay, together with the gifts of bread and wine, and makes all that were incensed an offering to God.
The priest then washes his hands. As the water is poured, he prays:
Wash me, O Lord, from my iniquity and cleanse me from my sin.
While this action of washing has a prayer attached to it, it was probably a very practical action. The priest had just received produce and animals in the offertory. However, the idea of washing before performing rituals and sacrifice goes back to the Old Testament, where Aaron and his sons are washed before performing their sacred duties (cf., Exodus, Chapter 40; Leviticus, Chapter 8). The priest likewise washes before entering into the ritual of sacrifice of the Mass. The next prayer prayed highlights the sacrifice…but more on that next week.
