OREMUS (LET US PRAY). — A general invitation in the Roman rite, addressed by the celebrant to the faithful before the prayers at Mass (Collects, Secret, Postcommunion, Pater noster), in the Office, and on other occasions.
On Good Friday, a brief address is added to the O., specifying the intention of the prayer: «Oremus, dilectissimi nobis, pro Ecclesia... pro Papa... ut Deus purget... auferat... indulgeat». To this invitation, more or less specific, there corresponded a prayer of the people, and in fact until the ninth century (cod. Vat. Ottobon. 313, in H. Lietzmann, Das Sacramentarium Gregorianum, Münster in V., 79, 2, n. 9) a few moments of prayer in silence followed. Outside Easter, on weekdays or days of penance, the people knelt at the deacon’s announcement Flectamus genus: then, at a second announcement, Levate, they rose again. The priest, as on feast days, after a few moments of prayer, gathered aloud the common sentiments of the faithful in a brief prayer, later called the «Collect», to which the people responded Amen. As this invitation was gradually shortened and the subsequent interval of silent prayer omitted, the O. became a simple introductory formula, joined directly to and immediately followed by the formula of the priest’s prayer; the ancient formula remains on the weekdays of the Ember Days, on Good Friday, and on Easter night. In the Collect of the Ambrosian rite the invitation of the O. is never used. In the Gallican liturgy the first Collect of the day is preceded by a Preface of varying length, sometimes even in the form of a short homily, delivered by the bishop to invite prayer and explain the feast of the day; the invitation to the other prayers is unknown, though perhaps the O. was used, as in the Roman rite (L. Duchesne, Origines du culte chrétien, Paris 1925, p. 113). The Mozarabic liturgy, on the other hand, uses the O. twice, before the Agios and the Pater noster. In the Eastern rites the invitation, delivered by the deacon, is always followed by a response from the people, Kyrie eleison or something similar. The invitation, sometimes as simple as
in the Roman rite, is more specific and detailed, especially in the prayer known as the prayer of the faithful. During the deacon’s prayer with the people, the prayer is recited by the priest (Byzantine rite). In practical usage, the word O. is also employed to signify the entire prayer that follows, to be said according to the circumstances.