說無垢稱經疏 4.3

4.3

贊曰：自下第九，命羅怙羅，初命、後辭。此初命也。羅怙羅，此云執日，本是執日阿脩羅名，《法華經》云羅睺阿脩羅王是也。此是非天前軍，非天將與帝釋鬪時，此為前軍。見日月天子放光遠射非天之眼，此非天乃以手執日障蔽其光。今此佛子取喻為名，亦復如是。佛法如日，由有此子，障我佛法智日之光，如彼非天，故以為名。古名宮生，耶輸被謗，設誓自明，實在宮生、非外他子，故名宮生。此子因緣，如經廣說，以昔為王，沙門求見，六日不覩；或塞鼠穴六日，障他母子絕食，故處胎中經六年住。後佛至迦維羅國，七日化千比丘皆形似佛，使之選佛，果至佛所，以明佛子。遂令舍利、目連度之，時年小矣。恐繁不述。

The Commentary says: From here on is the ninth [section], charging Rāhula: first is the charge, and second is the decline. This is the initial charge. Rāhula: here translated as ‘sun-grasper’, which was originally the name of a sun-grasping asura, as mentioned in the Lotus Sūtra: ‘the asura king Rāhu’. He was the vanguard of the asuras: when the asuras were about to battle with Śakra, he served as the vanguard. Seeing the gods of the sun and moon emitting light that shot afar into the eyes of the asuras, this asura grasped the sun with his hand to obscure its light. Now, this son of the Buddha was given his name based on this simile, and it is likewise so: the Buddha’s Dharma is like the sun; because of having this son, the light of the sun of wisdom of our Buddha's Dharma was obstructed, like that asura, so he was named after him. An ancient name was ‘Palace-born’: when Yaśodharā was slandered, she made a solemn vow to clarify herself, saying that he was truly born in the palace and not fathered by another, hence he was named ‘Palace-born’. The causes and conditions of this son are explained at length in the sūtras: because in a past life as a king he kept a śramaṇa who sought an audience waiting for six days without seeing him, or because he blocked a mouse's hole for six days, preventing mother and young from eating, he remained in the womb for six years. Later, when the Buddha went to Kapilavastu, in seven days he magically manifested a thousand monks who all resembled the Buddha, causing him to choose the Buddha; indeed he went to where the Buddha was, thereby making clear that he was the Buddha’s son. [The Buddha] then ordered Śāriputra and Maudgalyāyana to ordain him, at which time he was young. Fearing verbosity, I do not recount it in full.