I attended Mass today on Long Island in a nice church with a good choir and good preaching. Pretty good liturgy for these days, actually. But at the end of Mass the priest gave us the final blessing saying “May almighty God bless us, in the name of the Father, the Son and the Holy Spirit.”
Doesn’t sound so bad at first hearing, and in what follows, I’m not trying to beat up on this particular priest–its a common mistake. However, two things are problematic here, and they both stem from the priest’s lack of understanding of sacramental theology and his own role acting in persona Christi.
First of all, since the priest is acting as Christ, he should say “May Almighty God bless you,” the people. Christ has no need of the blessing of the Father, because he is one with the Father. To ask that God bless “us” means that:

a) the priest has given up acting in persona Christi and his blessing is only his and not Christ’s,
b) the priest is proclaiming that Christ is creature and not God and therefore needs a blessing from God.

Oops. Small word change, big heresy. His role is to be Christ at that moment, not part of the congregation.

Secondly, in the liturgy a priest does not give a blessing “in the name of the Father and the Son and the Holy Spirit.” The priest acting in persona Christi uses the words of Christ himself and therefore blesses the people in his own name, as Christ. He need not take the name (and therefore authority) of Christ; he is Christ, sacramentally speaking. The names of the persons of the Trinity are used here to describe who God is: Father, Son and Holy Spirit, not to invoke their authority. We make the Sign of the Cross at the beginning of Mass to recall our baptism, when we were baptized by a human being “in the name of” the Father, Son and Holy Spirit.

In the scheme of things, is this the biggest problem we have in the liturgy? Probably not. But since words mean things, and the fix is quite simple, let’s encourage our priests to use the words the Church gives us. Mother Church knows what she is doing.