10 “Shall one show Your loving-kindness in the grave, or Your faithfulness in destruction?”. The word “show” is of course understood as if repeated, Shall any show Your faithfulness in destruction? Scripture loves to connect loving-kindness and faithfulness, especially in the Psalms. “Destruction” also is a repetition of “the grave,” and signifies them who are in the grave, styled above “the dead,” in the verse, “Do you show wonders among the dead?” for the body is the grave of the dead soul; whence our Lord's words in the Gospel, “You are like whited sepulchres, which indeed appear beautiful outward, but within are full of dead men's bones, and of all uncleanness. Even so ye outwardly appear righteous unto men, but within you are full of hypocrisy and iniquity.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)