瑜伽論記 18.308

18.308

言生第四已上乃至亦名可愛異熟者，熟釋云：以下禪喜樂為方便，攝受第四定捨受故，彼諸第四定善業不苦不樂受現前時亦名可愛異熟也。又釋，第四定中說猗樂，為廣大喜樂也。

Regarding the passage from "born in the fourth or above…" to "also called agreeable fruition," an alternative explanation says: taking the joy and pleasure of the lower dhyānas as preparatory means, they sustain the equanimous feeling of the fourth dhyāna; therefore, when the neither-painful-nor-pleasant feeling of those wholesome karmas of the fourth dhyāna becomes manifest, it is also called agreeable fruition. Another explanation says: tranquility (praśrabdhisukha) spoken of in the fourth dhyāna is regarded as vast joy and pleasure.