Holy water is water blessed by a priest or bishop, and its everyday use marks the boundaries and passages of Christian life more than any dramatic power.
Sign of baptism
Kept in stoups at the doors of a church, holy water is taken on the fingers and used to make the sign of the cross on entering, a gesture that recalls baptism each time the threshold is crossed. It is sprinkled over people, buildings, objects and graves in blessing, and carried home for use by the family. The church treats it as a sacramental, an instituted sign that disposes the person to grace and expresses the prayer of the church, rather than as a substance working automatically, and that distinction is doctrinally important against the charge of magic.
Making and use
The blessing of the water, in the older form accompanied by the addition of blessed salt, sets it apart for these uses, and a larger blessing of water belongs to the Easter Vigil, from which the font is filled for baptism. The Eastern churches keep a great blessing of water at Epiphany, when rivers and seas are blessed and the water is drunk and kept through the year. The common thread is that the water recalls and extends baptism, so that the ordinary act of blessing oneself at a church door is a daily return to the sacrament by which a Christian enters the church.