Invitatory
Webster's Dictionary [1]
(1): ( a.) Using or containing invitations.
(2): ( n.) That which invites; specifically, the invitatory psalm, or a part of it used in worship.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]
is a short antiphon, suitable to the occasion, sung or recited before the Venite Exultemuts Dosmino, or interpolated between the verses of this psalm and the Gloria Patri also. The 95th Psalm, as an "invitation to praise," is supposed to have been used by the early ‘ Christians, adopted, no doubt, from the Temple service. In the Greek as well as the Latin churches it is still in use, though the two churches differ somewhat in form. In the East the following three clauses only are used:
"come, let us worship God our King;
O come, let us worship and fall down before Christ our King and God;
O come, let us worship before Christ himself, our King and God;"
but in the Western churches the whole psalm has always been used, accompanied generally by the invitatory, the latter varying, of course, according to the subject of the office to which they invite thought. It always consists of two clauses: "both are said before the psalm, and at the end of the second, seventh, and last verses; the second clause only at the end of the fourth and ninth verses. The Gloria Patsi is followed first by the second and then by both clauses. The Breviary of cardinal Quignones restricted the invitatory to the beginning and end of the psalms." The ninefold repetition of the whole or a part of the invitatory is of great antiquity. Durandus thus refers to its mystical bearing: "The invitatory is repeated six times at full length, because six is the first perfect number; and the sixfold repetition, therefore, sets forth the perfection with which we should endeavor to perform the service of God. Three is an imperfect number, and therefore the imperfect repetition takes place three times." On the double feasts of the Western Church the invitatory is doubled at matins, lauds, and vespers. In the English Church, where the order of daily prayer is chiefly taken from the corresponding offices of the Sarum Breviary (of which the rubric runs thus [after the Gloria and Alleluia]: "Sequatur invitatoriun hoc modo. Ecce venit rex. Occuramus obviam Salvatori nostro. Ps. Venite; post 1, 2 et v, vers. psalmi repetatur totum invitatorium. Post. 2, vers. 4 et 6, vers. psalmi repetatur solum hac pars, Occuramus. Et deinde reincipiatur totum invitatorium"), the opening sentences of matins and evensong are generally considered to be of a similar character, (compare Procter, Common Prayer, p. 182; Freeman, Principles of Divine Service, 1, 152 sq.). Blunt (Theol. Cyclop. 1, 356), however, says that the true invitatory of the English Church "is in the fixed vesicle ‘ Praise ye the Lord,' with its response, The Lord's name be praised.' The singing of Alleluia after the Gloria Patri, at the commencement of matins, was ordered in the Prayer-book of 1549. The response was inserted in 1661. The 95th Psalm, with this versicle and response, is to be considered as an unvarying invitatory in the modern English rite, exception Easter day, for which special provision is made.'. See also Neale, Liturgical Essays, p. 7 sq., et al.; Comment. on the Psalms, 1, 43 sq.; Walcott, Sacred Archeology, p. 332.
