On God is a phrase which is a way of saying that someone is telling the truth. Similar to another phrase such as "I swear to God." Other common uses are "On my mom," "On my grandma," "On my grandpa," "On gang," etc...

Intelligence agency term for "psychological operation". A government or corporate-sponsored operation, usually taking the form of a "terrorist attack" or "crazed gunman on a spree", with the intent of panicking the public into demanding more police and laws inhibiting freedom. Psyops are usually carried out by drugging a civilian or group of civilians with aggression-promoting drugs, psyching them up, arming them, and sending them out to commit mayhem. Government-sponsored terrorism. See also blackshirts, conspiracy

To swear upon the Christians all-father god.

A phrase used to describe something so honest you're swearing upon God's name.

I swear on God = On God