15 “Let them always be against the Lord”. “Against the Lord,” means in the Lord's sight: for other translators have rendered this line, “let them be always in the sight of the Lord;” while others have rendered it, “let them be before the Lord always;” as it is elsewhere said, “You have set our misdeeds in Your sight.” By “alway,” he means that this great crime should be without pardon, both here, and in a future life. “Let the memorial of them perish from off the earth:” that is, of his father and of his mother. By memorial of them, he means, that which is preserved by successive generations: this he prophesied should perish from the earth, because both Judas himself, and his sons, who were the memorial of his father and mother, without any succeeding offspring, as it is said above, were consumed in the short space of one generation....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)