A reader writes:
A protestant pastor recently asked why holy water is blessed. I did not have a good answer. Why is holy water blessed, and what does this blessing do above and beyond regular water?
Holy water is blessed in order to make it holy. Otherwise, it would just be water.
As to what the blessing does, it consecrates (sets apart) the water for sacred use. It is particularly used in baptism and, upon entering a church, in blessing oneself as a reminder of baptism (that’s why holy water fonts are set at the doors of churches, to remind us of how we entered the Church by baptism). In addition, holy water is used to bless other things and thus it serves as an acted out prayer by which we as God to bless whatever the holy water is being used on.
Holy water–like the other sacramentals–does not function like a sacrament. The Catechism of the Catholic Church notes:
Sacramentals do not confer the grace of the Holy Spirit in the way that the sacraments do, but by the Church’s prayer, they prepare us to receive grace and dispose us to cooperate with it. "For well-disposed members of the faithful, the liturgy of the sacraments and sacramentals sanctifies almost every event of their lives with the divine grace which flows from the Paschal mystery of the Passion, Death, and Resurrection of Christ. From this source all sacraments and sacramentals draw their power. There is scarcely any proper use of material things which cannot be thus directed toward the sanctification of men and the praise of God" [CCC 1670].
Like the other sacramentals, holy water thus serves as a means by which we can to something to signify our desire to consecrate ourselves and our circumstances to God, striking a connection with him in response to his grace and asking him to give us of his grace. They are, if you will, a kind of acted out prayer in which we and the Church implore God’s blessings.
Incidentally, although the above represents a Christian articulation of the role of holy water, holy water itself has been used in the service of God since Old Testament times. The book of Numbers records the use of holy water in a particular Old Testament ceremony (Num. 5:17). Even though that ceremony is not applicable to the present day, it illustrates the long history and the harmony of holy water with biblical truth. Since your friend is a Protestant pastor, this passage might help him appreciate the continuing use of holy water today (now with an explicitly Christ-centered understanding), building on the foundations that God laid in the Old Testament.

