Transfigurative harmonics

Bless your faithful, we pray, O Lord,
with a blessing that endures for ever,
and keep them faithful
to the Gospel of your Only Begotten Son,
so that they may always desire and at last attain
that glory whose beauty he showed in his own Body,
to the amazement of his Apostles.
Through.

Benedic, Domine, fideles tuos benedictione perpetua,
et fac eos Unigeniti tui Evangelio sic adhaerere,
ut ad illam gloriam, cuius in se speciem Apostolis ostendit,
et suspirare iugiter et feliciter valeant pervenire.
Per.

Bless, O Lord, your faithful with a perpetual benediction,

and cause them so to adhere to the Gospel of your Only Begotten,

that to that glory, the beauty [(species, appearance)] of which,
          [inherent] in himself, he to the apostles revealed,

they may have the strength both continually to sigh after
          and happily to attain.
Through.

     Prayer over the people, Second Sunday of Lent, Missale Romanum.

     I have translated species with "beauty" rather than "appearance" because it occurs in Is 53:2:  "there is no beauty in him [(non est species ei)], nor comeliness [(decor)]: and we have seen him, and there was no sightliness [(aspectus)], that we should be desirous of him" (Douay-Rheims 1899).  Among the Gospels, it occurs at this point only in Luke:  "the shape of his countenance [(species vultus eius, the appearance of his visage)] was altered" (Lk 9:29, Douay-Rheims 1899; RSV:  "his appearance was altered").  Though Matthew and Mark make Jesus allude to the cross on the way down from the mountain, Luke is the only Gospel in which Moses and Elijah (or the Law and the Prophets) speak "of his departure, which he was to accomplish at Jerusalem" (Lk 9:31 RSV).  It thus seems appropriate that it is only the Vulgate of Luke that makes this connection with the Vulgate of Isaiah, implying that the beauty that Isaiah denies Jesus on Mount Golgotha (but cf. Jn 12:28) he exhibits [(ostendit)] on the Mount of Transfiguration.

     I should note just quickly—without, however, following this up in the scholarship—that the Greek of Lk 9:29 (τὸ εἶδος τοῦ προσώπου αὐτοῦ ἕτερον) echoes the Greek of Is 53:2 (οὐκ ἔστιν εἶδος αὐτῷ οὐδὲ δόξα· καὶ εἴδομεν αὐτόν, καὶ οὐκ εἶχεν εἶδος οὐδὲ κάλλος) as well.

     I would also point out that "the Gospel of your Only Begotten [Son]" would of course be the voice from the cloud:  "This is my beloved Son/My Son, my Chosen."  (Yet in the prayer, the audite becomes an adhaerere.)

     According to Corpus orationum 14, pp. 161-162 ("60. Dominica II in Quadragesima"), this prayer was composed (for the new Missal) of Corpus orationum "I 875 + M[issale ]P[arisiense] 3141".

• Gregory the Great (669-731), Moralia in Job 29.25 (Noailles).  If this is a reference to the Gregorian treatment of Job 29:25, then that would be Moralia in Job, lib. 20, sec. 11 (in cap. 4), CCSL 143A, pp. 1009-1014, or PL 76, cols. 141, ff.  If, on the other hand, it is a reference to lib. 29, sec. 25 (in cap. 13), then that would be CCSL 143B, pp. _____, or PL 76, cols. 490, ff.  If, finally, it is a reference to lib. 29, cap. 25 (sec. 50), then that would be CCSL 143B, pp. _____, or PL 76, cols. 504, ff.  (Needless to say, I have not yet located the passage to which Corpus orationum refers.)
• Corpus orationum 1, no. 875 =Bruylants no. 154 (8th century Gelasian):  "Custodi, domine, quaesumus, ecclesiam tuam propitiatione perpetua et, quia sine te labitur humana mortalitas, tuis semper auxiliis et abstrahatur a noxiis et ad salutaria dirigatur" (I must confess that I don't see much of a parallel here).
• Missale Parisiense no. 3141 (1738), which derives from Gregory the Great (669-731), Moralia in Job 29.25 (Noailles):  "Celebrantes hoc sacrificio Unigeniti tui transfigurati mysterium; da nos, Deus, ipsius Evangelio sic adhaerere, ut ad illam gloriam, cuius in se speciem Apostolis ostendit, et suspirare iugiter, et feliciter pervenire valeamus.