Cyprian

But that the Church is one, the Holy Spirit declares in the Song of Songs, saying, in the person of Christ, "My dove, my undefiled, is one; she is the only one of her mother, she is the choice one of her that bare her." Concerning which also He says again, "A garden enclosed is my sister, my spouse; a spring sealed up, a well of living water." But if the spouse of Christ, which is the Church, is a garden enclosed; a thing that is closed up cannot lie open to strangers and profane persons. …

Epistle LXXV:2 ↗

Augustine of Hippo

"For as regards the fact that to preserve the figure of unity the Lord gave the power to Peter that whatsoever he should loose on earth should be loosed," it is clear that that unity is also described as one dove without fault. Can it be said, then, that to this same dove belong all those greedy ones, whose existence in the same Catholic Church Cyprian himself so grievously bewailed? For birds of prey, I believe, cannot be called doves, but rather hawks. …

On Baptism 3:17.22 ↗

Jerome

"My dove, my undefiled is but one; she is the only one of her mother, she is the choice one of her that bare her." Now the mother of whom this is said is the heavenly Jerusalem.

Letter 22.24 ↗

Bede

My dove is one, my perfect one. There are indeed sixty queens, because there are many faithful souls around the world who, having accepted the knowledge of the word, take on the task of multiplying the offspring of the Church for the reception of the heavenly kingdom. There are also eighty concubines, because there are also souls who, focused on earthly matters, engage in doctrine, and although they themselves succumb to carnal lures, nevertheless generate spiritual offspring for God by preaching. …

Commentary on the Song of Songs ↗