仁王護國般若波羅蜜多經疏 3.536

3.536

Explanation: "Have become […] entirely because in the past" explains that having long served many buddhas leads to the noble ones coming to be born, who undertake various enterprises to produce great benefit. As the Diamond Prajñā says: "In the last five hundred years after the Tathāgata's nirvāṇa, if there is someone who can produce faith and take this to be true, you should know that this person has planted roots of goodness under countless thousands of myriads of buddhas." How much more so when a king of humans promotes prajñā—could this be accomplished without having served many buddhas? Hereafter is the second part: explaining the arising of manifold difficulties.