13 In the next place there follows, “Of the Beloved, and of the beauty of the House to divide the spoils.” The repetition belongs to eulogy.... But whether it be repeated, or whether it be received as spoken once, the word which has been set down, namely, “Beloved,” I suppose that thus must be understood that which follows, “and of the beauty of a house to divide the spoils;” as if there were said, “Chosen even to divide the spoils of the beauty of a house,” that is, Chosen even for dividing the spoils.
For beautiful Christ has made His House, that is, the Church, by dividing to Her spoils: in the same manner as the Body is beautiful in the distribution of the members. “Spoils” moreover those are called that are stripped off from conquered foes. What this is the Gospel advises us in the passage where we read, “No one goes into the house of a strong man to spoil his vessels, unless first he shall have bound the strong man.” Christ therefore has bound the devil with spiritual bonds, by overcoming death, and by ascending from Hell above the Heavens: He has bound him by the Sacrament of His Incarnation, because though finding nothing in Him deserving of death, yet he was permitted to kill: and from him so bound He took away his vessels as though they were spoils.
For he was working in the sons of disobedience, of whose unbelief he made use to work his own will. These vessels the Lord cleansing by the remission of sins, sanctifying these spoils wrested from the foe laid prostrate and bound, these He has divided to the beauty of His House; making some apostles, some prophets, some pastors and doctors, for the work of the ministry, for the building up of the Body of Christ. For as the body is one, and has many members, and though all the members of the body are many, the body is one: so also is Christ. “Are all Apostles?
Are all Prophets? Are all Powers? Have all the gifts of healings? Do all speak with tongues? Do all interpret?” “But all these things works one and the same Spirit, dividing to each one his own gifts, as He wills.” And such is the beauty of the house, whereto the spoils are divided, that a lover thereof with this fairness being enkindled, cries out, “O Lord, I have loved the grace of Your House.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)