Objection 1. It would seem that the angels receive dowries. For a gloss on Canticle of Canticles 6:8, "One is my dove," says: "One is the Church among men and angels." But the Church is the bride, wherefore it is fitting for the members of the Church to have the dowries. Therefore the angels have the dowries.
Objection 2. Further, a gloss on Luke 12:36, "And you yourselves like to men who wait for their lord, when he shall return from the wedding," says: "Our Lord went to the wedding when after His resurrection the new Man espoused to Himself the angelic host." Therefore the angelic hosts are the spouse of Christ and consequently it is fitting that they should have the dowries.
Objection 3. Further, the spiritual marriage consists in a spiritual union. Now the spiritual union between the angels and God is no less than between beatified men and God. Since, then, the dowries of which we treat now are assigned by reason of a spiritual marriage, it would seem that they are becoming to the angels.
Objection 4. Further, a spiritual marriage demands a spiritual bridegroom and a spiritual bride. Now the angels are by nature more conformed than men to Christ as the supreme spirit. Therefore a spiritual marriage is more possible between the angels and Christ than between men and Christ.
Objection 5. Further, a greater conformity is required between the head and members than between bridegroom and bride. Now the conformity between Christ and the angels suffices for Christ to be called the Head of the angels. Therefore for the same reason it suffices for Him to be called their bridegroom.
On the contrary, Origen at the beginning of the prologue to his commentary on the Canticles, distinguishes four persons, namely "the bridegroom with the bride, the young maidens, and the companions of the bridegroom": and he says that "the angels are the companions of the bridegroom." Since then the dowry is due only to the bride, it would seem that the dowries are not becoming to the angels.
Further, Christ espoused the Church by His Incarnation and Passion: wherefore this is foreshadowed in the words (Exodus 4:25), "A bloody spouse thou art to me." Now by His Incarnation and Passion Christ was not otherwise united to the angels than before. Therefore the angels do not belong to the Church, if we consider the Church as spouse. Therefore the dowries are not becoming to the angels.
I answer that, Without any doubt, whatever pertains to the endowments of the soul is befitting to the angels as it is to men. But considered under the aspect of dowry they are not as becoming to the angels as to men, because the character of bride is not so properly becoming to the angels as to men. For there is required a conformity of nature between bridegroom and bride, to wit that they should be of the same species. Now men are in conformity with Christ in this way, since He took human nature, and by so doing became conformed to all men in the specific nature of man. on the other hand, He is not conformed to the angels in unity of species, neither as to His Divine nor as to His human nature. Consequently the notion of dowry is not so properly becoming to angels as to men. Since, however, in metaphorical expressions, it is not necessary to have a likeness in every respect, we must not argue that one thing is not to be said of another metaphorically on account of some lack of likeness; and consequently the argument we have adduced does not prove that the dowries are simply unbecoming to the angels, but only that they are not so properly befitting to angels as to men, on account of the aforesaid lack of likeness.
Reply to Objection 1. Although the angels are included in the unity of the Church, they are not members of the Church according to conformity of nature, if we consider the Church as bride: and thus it is not properly fitting for them to have the dowries.
Reply to Objection 2. Espousal is taken there in a broad sense, for union without conformity of specific nature: and in this sense nothing prevents our saying that the angels have the dowries taking these in a broad sense.
Reply to Objection 3. In the spiritual marriage although there is no other than a spiritual union, those whose union answers to the idea of a perfect marriage should agree in specific nature. Hence espousal does not properly befit the angels.
Reply to Objection 4. The conformity between the angels and Christ as God is not such as suffices for the notion of a perfect marriage, since so far are they from agreeing in species that there is still an infinite distance between them.
Reply to Objection 5. Not even is Christ properly called the Head of the angels, if we consider the head as requiring conformity of nature with the members. We must observe, however, that although the head and the other members are parts of an individual of one species, if we consider each one by itself, it is not of the same species as another member, for a hand is another specific part from the head. Hence, speaking of the members in themselves, the only conformity required among them is one of proportion, so that one receive from another, and one serve another. Consequently the conformity between God and the angels suffices for the notion of head rather than for that of bridegroom.
Source: Summa Theologica (New Advent)