俱舍論頌疏論本 3.37

3.37

論云：「如是三名因何而立？謂在見道，有未曾知，當知行轉，故說彼名未知當知。」解云：見道有十五心，謂八忍七智。此十五心於四諦境有未曾知，當知行相轉，如苦法忍與疑得俱生，未知苦諦，名未曾知。後至智位必當知故，名為當知。如苦忍既爾，諸餘七忍亦復如是，故忍總名未知當知。中間七智雖能正知，良由知諦未遍，中間起故，亦名未知當知，故說彼有見道行者，名未知當知也。

The treatise says: "Due to what are these three names established? On the path of seeing, because there is an activity consisting in coming to know what has not yet been known, it is therefore said that they are called 'one who will come to know what is not yet known'." The explanation states: The path of seeing has fifteen moments of mind, namely eight patiences (kṣānti) and seven knowledges (jñāna). Regarding the objects of the four noble truths, these fifteen moments of mind have an activity-mode of coming to know what has not yet been known operating. For instance, when the patience with the dharma of suffering (duḥkhe dharmajñānakṣānti) arises together with the attainment of doubt, having not yet known the truth of suffering is called "not yet known"; because later upon reaching the state of knowledge it will certainly come to be known, it is called "will come to know". Just as it is with the patience with suffering, so it is with the other seven patiences; therefore, the patiences as a whole are called "will come to know what is not yet known". Although the intermediate seven knowledges can know correctly, because their knowing of the truths is not yet complete and they arise in the middle, they are also called "will come to know what is not yet known"; therefore, practitioners possessing that path of seeing are called "those who will come to know what is not yet known".