Pax (liturgy)

[1] Jesus Christ and the Twelve Apostles quoted the formula from the Old Testament,[2][1] and they were preserved in the liturgy and Christian epigraphy.

Like the "Dominus vobiscum", they were first used in the liturgy, specifically in the form of "pax vobis", by the bishop in welcoming the faithful at the beginning of the Mass before the collect or oratio.

[1] When the Confiteor, introit, and Gloria in excelsis were later added to the Mass, the "pax vobis" and "Dominus vobiscum" were preserved.

There was a certain rivalry between the two formulae "pax vobis" and "Dominus vobiscum", and some councils, especially that of Braga in AD 561, ordained that both bishops and priests use the same form of salutation (for the texts, see the bibliography).

[1] "Te" of "tecum" and "vobis" are the ablative forms of the second person singular and plural pronouns, respectively; both are translated in English as "you" (or “thee” and “you” respectively).