四分律行事鈔資持記 1.367

1.367

釋明相中，初科。後夜者，據近顯相，遠則可知。律中結界廣故，十四日布薩，十三日往，不得受欲。

In explaining "the appearance of light": The first section. "The later part of the night" is stated with reference to the imminent appearance of light; that which is far off can be known by inference. Because boundaries established in the Vinaya are extensive, if for the poṣadha on the fourteenth day one goes on the thirteenth day, one cannot receive chanda.