4 Whose voice is the Psalm? “Of Asaph.” What is Asaph? As we find in interpretations from the Hebrew language into the Greek, and those again translated to us from the Greek into the Latin, Asaph is interpreted Synagogue. It is the voice therefore of the Synagogue. But when you have heard Synagogue, do not immediately abhor it, as if it were the murderer of the Lord. That Synagogue was indeed the murderer of the Lord, no man doubts it: but remember, that from the Synagogue were the rams whereof we are the sons.
Whence it is said in a Psalm, “Bring ye to the Lord the sons of rams.” What rams are thence? Peter, John, James, Andrew, Bartholomew, and the rest of the Apostles. Hence also he too at first Saul, afterwards Paul: that is, at first proud, afterwards humble....Therefore even Paul came to us from the Synagogue, and Peter and the other Apostles from the Synagogue. Therefore when you have heard the voice of the Synagogue, do not look to the deserving thereof, but observe the offspring.
There is speaking therefore in this Psalm, the Synagogue, after the failing of the hymns of David, the son of Jesse that is, after the failing of things temporal, through which God was wont to be praised by the carnal people. But why did these fail, except in order that others might be sought for? That there might be sought for what? Was it things which were not there? No, but things which were there being hidden in figures: not which were not yet there, but which there as it were in a sort were concealed in certain secret things of mysteries. What things? “These,” says the Apostle himself, “were our figures.”...
Source: The Enarrations, or Expositions, on the Psalms (New Advent)