5 As if you should ask again, who are the beloved? “Lo, children, the reward of the fruit of the womb, are an heritage of the Lord”. Since he says, “fruit of the womb,” these children have been born in travail. There is a certain woman, in whom what was said unto Eve, “in sorrow shall you bring forth children,” is shown after a spiritual manner. The Church bears children, the Bride of Christ; and if she bears them, she travails of them. In figure of her, Eve was called also “the Mother of all living.” He who said, “My little children, of whom I travail in birth again, until Christ be formed in you,” was among the members of her who travails. But she travailed not in vain, nor brought forth in vain: there will be a holy seed at the resurrection of the dead: the righteous who are at present scattered over the whole world shall abound. The Church groans for them, the Church travails of them; but in that resurrection of the dead, the offspring of the Church shall appear, pain and groaning shall pass away....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)