In Dragon Magazine #92, Gary Gygax wrote and article discussing that the way Cleric's get their spells isn't really written in stone and you as the DM can change it up a bit.

Clerics and druids have access to all spells without needing spell books, as their powers are granted by their deities. While the rules allow flexibility, experienced Dungeon Masters may alter these to enhance gameplay. The balance of power is crucial, allowing for the removal or addition of spells based on character faithfulness and the campaign’s needs. This can lead to interesting dynamics, such as withholding spells from unfaithful clerics or druids.

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