大般涅槃經義記 4.221

4.221

第三句中，「見乳同色尋便」驚等，釋有二義：一對上初義，就佛所化凡夫二乘以釋其言，凡夫二乘聞佛宣說三乘性一名為見乳同一白色，執相疑性名「尋驚怪牛色各異，乳云何一」；二對上後義，約就修行菩薩以解，修行菩薩證性一味名見其乳同一白色，執相疑真，故言「尋怪牛色各異，乳云何一」。

In the third line, "seeing that the milk was of the same color, he immediately was astonished," etc., has two meanings in explanation: first, corresponding to the first meaning above, the words are explained in terms of the ordinary persons and those of the two vehicles transformed by the Buddha: ordinary persons and those of the two vehicles hearing the Buddha expound that the nature of the three vehicles is one is called "seeing that the milk was uniformly white in color," and grasping marks and doubting the nature is called "immediately being astonished that the cows were of various different colors, so how could the milk be one?"; second, corresponding to the latter meaning above, it is explained in terms of the practicing bodhisattva: the practicing bodhisattva realizing that the nature is of one taste is called "seeing that the milk was uniformly white in color," and grasping marks and doubting the true, it therefore says "immediately marveling that the cows were of various different colors, so how could the milk be one?"