In persona Christi

"In persona Christi" - a Latin phrase meaning "in the person of Christ" - is an important theological concept of the Catholic Church and the confessional lutheran Church which refers to the action of a bishop or priest, often assisted by a deacon (though deacons can only celebrate the Sacrament of Baptism and witnessing the Sacrament of Marriage) while celebrating a sacrament. The priest acts in the person of Christ, or it could be said, the Person of Christ is acting through the performance of the gesture and the pronouncing of the words of the sacramental rite.

In particular, there are essential moments in the rites where the priest's words and gestures confect the sacrament. These words are spoken "in persona Christi capitis". Two examples include "This is my body" and "This is my blood" in the Eucharistic prayer and "God, the Father of mercies, through the death and resurrection of his Son has reconciled the world to himself and sent the Holy Spirit among us for the forgiveness of sins; through the ministry of the Church may God give you pardon and peace, and I absolve you from your sins in the name of the Father, and of the Son, and of the Holy Spirit." in the Sacrament of Reconciliation.