仁王般若經疏 1.67

1.67

時無色界者，有人解云：無色界雖無麁色，有其細色。今解不然。色無色相而無色不色，故云無色界。色欲諸天既聞般若，歡喜雨華供養。就中有三：初無色界天雨華、二色界天雨華、三欲界六天雨華。無色界雨華中有三子句，初雨無量大香華、二香如車輪、三華如須彌山，如雲而下。

"At that time, the formless realm": some explain this by saying: Although the formless realm lacks coarse form, it has subtle form. The present explanation is not so. Form is devoid of the mark of form, yet there is no form that is not form; therefore it is called the formless realm. When the devas of the form and desire realms heard prajñā, they rejoiced and rained down flowers in offering. Within this there are three: first, the devas of the formless realm rain down flowers; second, the devas of the form realm rain down flowers; third, the devas of the six desire realms rain down flowers. Within the raining down of flowers by the formless realm there are three subordinate clauses: first, raining down countless large fragrant flowers; second, their fragrance was like cartwheels; third, the flowers were like Mount Sumeru, descending like clouds.