請觀音經疏闡義鈔 3.12

3.12

「此土至令請」者，因緣和合能破三障故。「一法標名」者，隨機各立一號也。「今欲」下，明須請之由。由表三德，故須俱請。今此土眾生欲消伏三障毒害，必須外假勝境之緣，顯發自己法身之理。彌陀勝境既表法身，故須請也。而此法身為感所覆，今欲顯發，須修觀慧照了此理，除其惑障。觀音表慧，故須請也。然慧不孤運，假福資成。勢至表福，亦須請也。釋迦欲令眾生顯發本理學慧修福，故請三聖密以表之。

Regarding "From this land up to having them invoke": this is because the combination of causes and conditions can shatter the three obstacles. Regarding "designating names by a single dharma": names are established individually in accordance with capacities. From "Now wishing" below: this clarifies the reason why they must be invoked. Because they represent the three virtues, they must all be invoked. Now, when sentient beings of this land wish to eliminate and subdue the poisons of the three obstacles, they must externally rely on the conditions of superior objects to manifest and activate the principle of their own Dharma body. Since Amitābha's superior object represents the Dharma body, he must be invoked. Yet this Dharma body is covered by emotional defilements; wishing to manifest it now, one must cultivate contemplative wisdom to illuminate this principle and remove the obstacles of delusion. Avalokiteśvara represents wisdom, and therefore must be invoked. However, wisdom does not operate in isolation; it relies on merit to support and complete it. Mahāsthāmaprāpta represents merit, and therefore must also be invoked. Śākyamuni wished to cause sentient beings to manifest their fundamental principle, learn wisdom, and cultivate merit; therefore, he had them invoke the three holy ones to secretly represent them.