an act of God Formal

Meaning: Something like an earthquake or a tornado can be called an act of God.

For example:

• Will your insurance policy pay for the cost of replacing your house if it's destroyed by an act of God?
  
• My daughter said that if disasters that kill lots of people are acts of God, why does He do it. I didn't know what to say.
  

Origin: The phrase 'act of God' originally appeared in religious texts, though nowadays it is mostly found in legal texts.