In Vain Meaning

(idiomatic) In a disrespectful manner, especially when concerning religion.

Example: 1863 November 19, Abraham Lincoln, The Gettysburg Address, based on the signed "Bliss Copy"
  we here highly resolve that these dead shall not have died in vain
19C, Friedrich Nietzsche
  On the mountains of truth you can never climb in vain
1611, Bible (KJV):, Exodus 20:7
  Thou shalt not take the name of the LORD thy God in vain