Remembering things is the primary purpose of the check, but sometimes how you're applying it might require an alternative skill check to make sense. Here are some examples (from https://rpgbot.net/dnd5/characters/impractical-skill-checks/ ):

Wisdom – Consoling and counselling a creature through a crisis of faith could be done with a Wisdom (Religion) check.

Charisma – Proselytizing for a faith makes more sense as a Charisma (Religion) check than a Charisma (Persuasion) check.