Actually, it is a Forgotten Realms thing.
In the Forgotten Realms, all Divine magic is provided exclusively by deities. While in other settings, a Cleric would be able to get power from some vague philosophical ideal, in the realms, only deities grant such power.
All Divine classes, Druids, Rangers, Paladins, Clerics and all others, are granted powers by a deity and only a deity in the Forgotten Realms. At least before 4th Edition, I don't know what happens after the Spellplague.
EDIT: Note that certain powerful local nature spirits (such as those of Rashemen) are on par with demigods or even minor deities, and as such are able to grant spells to druids of the local area. Though most druids still draw spells from one of the bigger nature gods, Silvanus (for the hardliners) and Chauntea (for the much more moderate) being favorites.
In the Forgotten Realms, all Divine magic is provided exclusively by deities. While in other settings, a Cleric would be able to get power from some vague philosophical ideal, in the realms, only deities grant such power.
All Divine classes, Druids, Rangers, Paladins, Clerics and all others, are granted powers by a deity and only a deity in the Forgotten Realms. At least before 4th Edition, I don't know what happens after the Spellplague.
EDIT: Note that certain powerful local nature spirits (such as those of Rashemen) are on par with demigods or even minor deities, and as such are able to grant spells to druids of the local area. Though most druids still draw spells from one of the bigger nature gods, Silvanus (for the hardliners) and Chauntea (for the much more moderate) being favorites.