INCENSING THE ALTAR.
The Altar represents our Lord Jesus Christ. The Saints’ Relics which are there, remind us that the Saints are His members. For, having assumed our human nature, He not only suffered His Passion, triumphed in His Resurrection, and entered into His glory by the Ascension, – but He, also, founded the Church upon earth, and this Church is His mystical Body; He is its Head, and the Saints are its members. From this point of view, then, our Lord has not the fullness of His mystical Body without His Saints; and it is for this reason, that the Saints, who are reigning with Him in glory, are united with Him, in the Altar, which represents Him.
The Priest, having finished the prayer, which he said bowing down, and his hands joined on the Altar, prepares for its Incensing. Twice will this take place during the Holy Sacrifice, and both times with much solemnity, out of respect for our Lord, who is signified by the Altar, as we have already said. Nevertheless, the Priest does not recite any prayer during the first Incensing; he merely thurifies every portion of the Altar, in such wise as that the whole of it is thus honoured. We learn from the Book of Leviticus, that Incense was used, at a very early period, in the divine worship.
The blessing, which the Priest gives it in the Mass, raises this production of nature to the supernatural order. Holy Church has borrowed this ceremony from heaven itself; where St. John witnessed it. In his Apocalypse, he saw an Angel, standing, with a golden censer, near the Altar, on which was the Lamb, with four-and-twenty elders around him. (Apoc. viii. 3.) He describes this Angel to us, as offering to God the prayers of the Saints, which are symbolised by the incense.
Thus, our holy Mother the Church, the faithful Bride of Christ, wishes to do as heaven does; and taking advantage of the veil of its mysterious secrets being even thus partially raised up by the Beloved Disciple, she borrows, for our earth’s imitation, the tribute of honour thus paid, yonder above, to the glory of her Spouse. At this part of the Mass, the Altar alone, and the Priest, are thurified; the incensing of the Choir is reserved for the second time of the ceremony, which is at the Offertory. – It is one of the customs of the Church to expose, on the Altar, images and relics of the Saints, which then are incensed at the same time.
INTROIT.
The ceremony of the Incensing completed, the Priest says the Introit. Formerly, this was not done. The Ordo of St. Gregory tells us, that the Priest vested in the Secretarium, and then went to the Altar, preceded by the Cross and Torches; during which time, the choir sang the Introit, which was longer than we now have it, for the entire Psalm was sung, and not merely one or two of its verses, with the Gloria Patri, as at present. In like manner, it was the choir alone that took the remaining portions, which were to be sung during the Mass. The custom of the Priest’s reciting these several portions, originated with that of Low Mass, which custom was, at last, introduced into High Masses.
These remarks will explain how it is, that the ancient Missals differ considerably from those which are now in use. They simply contain the Prayers: Collects, Secrets, Postcommunions, Prefaces, and the Canon. They were called Sacramentaries. Whatever was sung by the choir was inserted in the Antiphonarium, which now goes under the name of Gradual. (Most of the chanted portions of the Mass are, really, nothing more than Antiphons; only, they have more notes than what ordinary Antiphons have.) In more modern times, ever since Low Masses were introduced, our Missals contain everything that used, formerly, to be sung by the Choir; as also the Epistles and Gospels.
Both the Priest and the Choir make the sign of the Cross at the beginning of the Introit, because it is considered as the opening of the Readings. In Masses for the Dead, the Priest makes the Cross over the Missal only.
KYRIE.
Next follows the Kyrie, which, at a High Mass, is said at the same side of the Altar, where the Introit was read. The Priest is accompanied by his Ministers, who do not go to the middle of the Altar, until he himself does; meanwhile, they stand behind him, on the steps.
In a Low Mass, the Priest says the Kyrie, in the middle. This prayer is a cry of entreaty, whereby the Church sues for mercy from the Blessed Trinity.
The first three invocations are addressed to the Father, who is Lord: Kyrie, Eleison; (Lord, have mercy). The following three are addressed to Christ, the Son incarnate: Christe, eleison. The last three are addressed to the Holy Ghost, who is Lord, together with the Father and the Son; and therefore, we say to Him also: Kyrie, eleison. The Son, too, is equally Lord, with the Father and the Holy Ghost: but, holy Church here gives Him the title of Christ, because of the relation this word bears to the Incarnation.
The Choir, too, takes up the same nine invocations; and sings them. Formerly, it was the practice, in many Churches, to intersperse them with words, which were sung to the same melody as the invocations themselves, as we find in several old Missals. The Missal of St. Pius the Fifth did away, almost entirely, with these Kyrie, called, on account of these popular additions, Farsati, (in French, farcis).
When the Pope celebrates a Solemn Mass, the singing of the Kyrie is continued during the act of homage which is paid him on his throne: but this is an exception to the present observance throughout the Church. The three invocations, each repeated thrice over, (as now practised,) are like a telling us of our union, here below, with the nine choirs of Angels, who sing, in heaven, the glory of the Most High. This union prepares us to join them in the Hymn which is now to follow, and which these blessed Spirits brought down to this our earth.
Again from the notes of Dom Berengeur, at the Sancta Missa website.