瑜伽論記 4.244

4.244

言無色想者，依無色定意意解思惟故，外者除眼等根意解思惟餘色故，據實初二通觀內外而有兼正，但欲顯第二解脫已離色欲故，別標內無色想，其初解脫未離色欲，內外俱有色故但言有色，號內有色於理何傷。

The words "notion of formlessness" mean mental engagement through resolution relying on formless meditation. "External" means mental engagement through resolution excluding the sense faculties such as the eyes, regarding the remaining forms. In fact, the first two both contemplate internal and external, though with secondary and primary emphases. However, simply wishing to show that the second liberation has already separated from desire for form, it is distinctly designated as "internally having the notion of formlessness"; as the first liberation has not separated from desire for form, and form exists both internally and externally, it merely says "having form." What harm is there to the principle if it is called "internally having form"?