佛頂尊勝陀羅尼經教跡義記 2.86

2.86

唐云一切諸佛加持清淨也。解曰：一切諸佛者，是十方諸佛也。為修瑜伽觀行三密齊修，念誦功成身心清淨，諸佛歡喜雲集道場，摩頂此人，故曰加持也。

In Chinese it means: "Empowered and purified by all Buddhas." The explanation states: "All Buddhas" means the Buddhas of the ten directions. Because one cultivates yoga contemplation and practices the three mysteries together, when the merit of recitation is accomplished, body and mind are purified; the Buddhas rejoice, gathering like clouds at the bodhimaṇḍa, and crown this person's head with their hands; hence it is called "empowerment."