We have a little sister, and she has no breasts: what shall we do for our sister in the day when she shall be spoken for?
All Commentaries on Song of Songs 8:8 Go To Song of Songs 8
Aquinas Study Bible
AD 2017
little sister: that is, the Church, which is called the sister of Christ for the same reason that Christ is called her brother at the beginning of this chapter, is little, that is, humble and despised by the people of this present age, which was the case up to the time of Constantine.
has no breasts: that is, the Church did not have the freedom to pour out the milk of sacred doctrine through the preaching of the Catholic faith, which the Church did not dare to preach publicly at that time, but only in secret, except for some saints who offered themselves voluntarily to be killed for preaching the faith.
What shall we do: By "we" the Father and the Holy Spirit are understood to be working with the Son. For the activities of the Trinity are indivisible. (Nicholas of Lyra)
spoken to: that is when the Church is called on more abundantly from all parts of the world, though early on She was being prepared for greater growth. (St. Anselm)
