起信論疏筆削記 17.44

17.44

復有五意，故在彼天：一、以二乘人執化八相為真佛，不信別有聖人，又不知即心是佛，又信彼第四禪中是聖人生處。今且同與二乘在彼天處，攝示令知八相非真，故在此天。二、緣三災不及，故當此天。三、緣欲界色質麁重，是有；無色界都無色質，是無。今此天中表離有無，契於中道，故在此天。四、為摩醯首羅天王面有三目，不縱不橫，表證三德，涅槃亦爾，故在此天。五、為下界慧多定少，上界四空定多慧少，此天定慧平等，故在此天。以禪者翻云靜慮，靜揀於下，慮揀於上，偈云：欲界及無色，佛不於彼成。色界中上天，離欲中得道。

There are further five reasons why [the manifestation occurs] in that heaven: First, because practitioners of the two vehicles cling to the transformation [body] of the eight phases as the true Buddha, disbelieving that there is any other sage, and furthermore do not know that mind itself is Buddha, yet they believe that fourth dhyāna is the birthplace of sages. Now, by being temporarily together with the two vehicles in that heaven, [the Buddha] gathers and shows [them], causing them to know that the eight phases are not real; hence [he appears] in this heaven. Second, because the three disasters do not reach it, it corresponds to this heaven. Third, because the material form of the desire realm is coarse and heavy, which is existence; whereas the formless realm has no material form at all, which is non-existence. Now, this heaven expresses freedom from both existence and non-existence and accords with the Middle Way; hence [he appears] in this heaven. Fourth, because King Maheśvara has three eyes upon his face that are neither vertical nor horizontal, expressing the realization of the three virtues, and nirvāṇa is likewise so; hence [he appears] in this heaven. Fifth, because in the lower realms there is much wisdom and little meditative concentration, while in the upper four formless realms there is much concentration and little wisdom; this heaven possesses concentration and wisdom in equal measure, hence [he appears] in this heaven. For “dhyāna” is translated as “tranquil contemplation” (cintā): tranquility excludes the lower, and contemplation excludes the upper. A verse states: / In the desire realm and the formless realm, / the Buddha does not attain [awakening] therein; / in the highest heaven of the form realm, / he attains the Way amidst freedom from desire.