Most of the time when we dip our fingers into the holy water font, either at church or at home, we simply make the sign of the cross and go about our way.
Making the sign of the cross with holy water is a prayer in itself and asks the Holy Trinity to surround us with protection and grace.
However, there is also an additional prayer that can be said (though certainly not required) that is found in the Golden Manual. It is a short prayer that is taken directly from Psalm 51, and perfectly summarizes the symbolism found in using holy water to bless ourselves.
Water is always seen in Christian theology as a means of purification, and so we ask God to cleanse us every time we use holy water. Below is the optional prayer that can lead to a more fruitful experience of dipping your fingers into the holy water font.
By this holy water and by Your Precious Blood, wash away all my sins, O Lord.
St. Theresa of Avila on holy water: “From long experience I have learned that there is nothing like holy water to put devils to flight and prevent them from coming back again. They also flee from the cross, but return; so holy water must have great value.”
Holy water is a means of spiritual wealth — a sacramental that remits venial sin. The Church strongly urges its use, especially when dangers threaten. The devil hates holy water because of its power over him. He cannot long abide in a place or near a person that is often sprinkled with this blessed water.