"God only knows"
I don't believe in gods, not YHWH, not Mazda, not Zeus. So what do the above phrases mean to me?
"God only knows": No one knows.
"one nation under God": a nation under the sovereignty of no person, a nation beneath no one
"in God we trust": we trust in no individual persons, not in kings or pontiffs (but rather in laws and principles)
"God bless you": may you be blessed
"God-given rights": rights given us by no one, there is no person in whose name we have rights
Certain religious sayings make more sense when you insert the word "nothing" in place of the word "God."
"When you die, you become one with God."
"They're in God's hands now."
"God has a special plan for your life."
"Before there was a universe, there was God."
"Homosexuality is an abomination before God."
Proof that God Exists (Probably): error and belief