"It chills my blood to hear the blest Supreme Rudely appealed to on each trifling theme"

This quote by William Cowper talks to the idea of people taking the Lord's name in vain. He is expressing his shock and dismay at how casually people invoke the name of the Supreme Being in everyday conversations. He finds it disrespectful and inappropriate to use the Lord's name in such a method, and it cools his blood to hear it. He believes that the Lord needs to only be invoked in matters of excellent significance, not for insignificant matters. Cowper's quote serves as a tip to be mindful of how we use the Lord's name and to just invoke it in matters of terrific importance. It is a pointer to show respect and reverence for the Lord and to not take His name in vain.