24 “Bless ye the Lord, you Angels of His, you that are mighty in strength: ye that fulfil His word”. By the word of God, then, you are not righteous, nor faithful, unless when thou dost it. “You that are mighty in strength, you that fulfil His commandment, and hearken unto the voice of His words.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)