請觀音經疏 1.21

1.21

問：何意請彼佛耶？答：此土請釋迦，為消伏之因。彼佛二菩薩為外緣，因緣應在二佛，故勸令請。又就彼佛表如來法身實相之境，觀音表中道正觀之智，大勢表福德神力熏修。但聖人皆具三德無不具足，今各據一門的當為語，三人各從一法標名。今欲消伏毒害，必須勝境顯發法身，亦須智慧照了除惑，亦須福德資成智慧，是故三聖俱請。

Question: For what reason does one invite that Buddha? Answer: Invoking Śākyamuni in this land serves as the internal cause for dispelling and subduing; that Buddha and the two bodhisattvas serve as the external conditions. Since the stimulus and response of cause and conditions reside in the two Buddhas, he therefore exhorts them to make the invocation. Furthermore, that Buddha represents the objective realm of the Tathāgata's dharmakāya and true mark; Guanyin represents the wisdom of the correct contemplation of the Middle Way; Mahāsthāmaprāpta represents the pervasive cultivation through meritorious virtue and spiritual power. However, the sages are each fully endowed with the three virtues, lacking none; now each takes one approach as a direct expression, and the three persons are each designated by one dharma. Now, wishing to dispel and subdue poisonous harms, one must rely on the superior realm to reveal the dharmakāya, must also rely on wisdom to illuminate and eliminate delusions, and must also rely on meritorious virtue to support and accomplish wisdom; therefore, all three sages are invited together.