13 What here understand we, “Set your hearts upon her might, and distribute her houses”? That is, distinguish house from house. Do not confound. For there is a house having the form of godliness, and not having godliness; but there is a house having both form and godliness. Distribute, confound not. But then ye distribute and confound not, when you “set your hearts upon her might;” that is, when through love you are made spiritual. Then ye will not judge rashly, then you will see that the evil harms not the good as long as we are in this floor.
“Distribute her houses.” There can be also another understanding. The two houses, one coming of the circumcision, one of the uncircumcision, it is commanded the Apostles to distribute. For when Saul was called, and made the Apostle Paul, agreeing in unity with his fellow Apostles, he so with thorn determined, that they should go to the circumcision, he to the uncircumcision. By that dispensation of their Apostleship, they distributed the houses of the city of the great King; and meeting in the corner, divided the Gospel in dispensation, in love united it.
And truly this is rather to be understood; for it follows and shows that it is here said to the preachers, “distribute her houses: that you may tell it to the generation following:” that is, that even to us, who were to come after them, their dispensation of the Gospel should reach: For not for those only they laboured, with whom they lived in the earth; nor the Lord for those Apostles only to whom He deigned to show Himself alive after His Resurrection, but for us also. For to them He spoke, and signified us when He spoke, “Lo, I am with you always, even to the end of the world.” Were they then to be here always, even to the end of the world?
Also He said, “Neither pray I for these alone, but for them also which shall believe in Me through their word.” Therefore He considers us, because He suffered on account of us. Justly then it is said, “That ye may tell it to the generation following.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)