Most Paladins are sworn to a deity. But all Paladins recieve their powers from deities, whether or not they are aware of it or not. Thats a given. Their powers and spells use Divine magic, they use Holy symbols, they recieve powers before they swear oaths (if you want to go technical).
Their powers dont come from Thin air.
An aasimar or part god (Bhallspawn, etc) sure. But they still recieve powers from deities. They are just born with it/its in their blood.
"They say he who smelt it dealt it." Sooo technically... this burnt corpse is your fault officer."