10 Then he turns to God in prayer against the enemies of that city. “Remember, O Lord, the children of Edom”. Edom is the same who is also called Esau: for you heard just now the words of the Apostle read, “Jacob have I loved, but Esau have I hated.”...Esau then signifies all the carnal, Jacob all the spiritual....All carnal persons are enemies to spiritual persons, for all such, desiring present things, persecute those whom they see to long for things eternal. Against these the Psalmist, looking back to Jerusalem, and beseeching God that he may be delivered from captivity, says— what?
“Remember, O Lord, the children of Edom.” Deliver us from carnal men, from those who imitate Esau, who are elder brethren, yet enemies. They were first-born, but the last-born have won the pre-eminence, for the lust of the flesh has cast down the former, the contempt of lust has lifted up the latter. The other live, and envy, and persecute. “In the day of Jerusalem.” The day of Jerusalem, wherein it was tried, wherein it was held captive, or the day of Jerusalem's happiness, wherein it is freed, wherein it reaches its goal, wherein it is made partaker of eternity?
“Remember,” says he, “O Lord,” forget not those “who said, Rase it, rase it, even to the foundation thereof.” Remember then, it means, that day wherein they willed to overthrow Jerusalem. For how great persecutions has the Church suffered! How did the children of Edom, that is, carnal men, servants of the devil and his angels, who worshipped stocks and stones, and followed the lusts of the flesh, how did they say, “Extirpate the Christians, destroy the Christians, let not one remain, overthrow them even to the foundation!” Have not these things been said? And when they were said, the persecutors were rejected, the martyrs crowned....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)