5 “Your children.” The wife and the children are the same. In these carnal marriages and wedlocks, the wife is one, the children other: in the Church, she who is the wife, is the children also. For the Apostles belonged to the Church, and were among the members of the Church. They were therefore in His wife, and were His wife according to their own portion which they held in His members. Why then is it said concerning them, “When the Bridegroom shall be taken from them, then shall the children of the Bridegroom fast”? She who is the wife, then, is the children also. I speak a wonderful thing, my brethren. In the words of the Lord, we find the Church to be both His brethren, and His sisters, and His mother....For Mary was among the sides of His House, and His relatives coming of the kindred of the Virgin Mary, who believed on Him, were among the sides of His House; not in respect of their carnal consanguinity, but inasmuch as they heard the Word of God, and obeyed it....He added; “For whosoever shall do the will of My Father which is in heaven, the same is My brother, and sister, and mother.” “Brother,” perhaps, on account of the male sex whom the Church has: “sister,” on account of the women whom Christ has here in His members. How “mother,” save that Christ Himself is in those Christians, whom the Church daily brings forth Christians through baptism? In those therefore in whom you understand the wife, in them you understand the mother, in them the children.
6....Such children ought therefore to be “around” the Lord's “table, like olive-branches.” A complete Vine it is, a great bliss: who would now refuse to be there? When you see any blasphemer have a wife, children, grandchildren, and yourself perchance without them, envy them not; discern that the promise has been fulfilled in you also, but spiritually. If therefore we have, why have we? Because we fear the Lord. “Lo, thus shall the man be blessed that fears the Lord”. He is the man, who is also the men; and the men are one man; because many are one, because Christ is One.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)