Although it is most common for Mass to begin with a penitential act, this is not always so. The rules for Mass indicate that it is always omitted when baptismal or funeral rituals begin the Mass, for example, or when the Eucharist immediately follows the celebration of the Liturgy of the Hours (say, Morning or Evening Prayer).
A more common substitution for a penitential ritual is the sprinkling rite, in which holy water is used by the clergy and congregation as a reminder of baptism. It is most appropriate during the Easter season, of course – each year this is “standard practice” at the Cathedral, for example – but it is permitted at any Sunday Mass in any season.
Holy water used in this way, as a sign of blessing, is a very basic religious action. Almost every religion, including the Judaeo-Christian “faith-family,” makes use of ritual washings in its prayer. When “special” water is used, and deliberately cast copiously and indiscriminately upon every one by a representative of God, there is the added symbolic reflection of God’s grace, which is given by Him in abundance. In our Mass an infinite sharing of God’s own life is offered, and so our rituals reflect what’s happening!