10 “The fear of the Lord is chaste, enduring for ever”. “The fear of the Lord;” not that distressing fear under the law, dreading exceedingly the withdrawal of temporal goods, by the love of which the soul commits fornication; but that chaste fear wherewith the Church, the more ardently she loves her Spouse, the more carefully does she take heed of offending Him, and therefore, “perfect love casts” not “out” this “fear,” but it endures for ever.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)