There are threescore queens, and fourscore concubines, and virgins without number.
All Commentaries on Song of Songs 6:8 Go To Song of Songs 6
Aquinas Study Bible
queens are those who devote themselves to the teachings of the kingdom of heaven.
Concubines are those who proclaim Christ along with love for worldly things.
Maidens without number are those who devote themselves to obey the commandments though they are not teachers or preachers. (St. Bede)