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The Spring of Power is a Shrine quest in The Legend of Zelda: Breath of the Wild. It is a quest given to Link by Nobo at the East Akkala Stable. She tells link about a legend regarding a "sacred relic" and a spring to the west of the stable. When he arrives at the Spring of Power, the goddess Hylia asks that he offer Dinraal's Scale to the spring. Once this is done, a door opens behind the statue revealing Tutsuwa Nima Shrine and the quest is completed.
Spoiler warning: Spoilers end here.