大佛頂如來放光悉怛多般怛羅大神力都攝一切呪王陀羅尼經大威德最勝金輪三昧呪品 1.94

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「復次若有一切法不成驗，皆由業障在身。取東流水呪七遍，以灌呪師頂上，即得神驗，令彼呪神心生附著。

Furthermore, if all rites fail to achieve efficacy, it is entirely due to karmic hindrances in the body. Take water flowing east, empower it seven times with the mantra, and pour it over the head of the mantra master; he will immediately attain divine efficacy, causing the mantra deity's mind to adhere to him.