四分律刪繁補闕行事鈔 2.377

2.377

一一心門。唯就作業以明，但塞不通；以心無並慮，境不頓現故也。

First, the section of the single mind. Clarified solely with reference to performing karma, it is only obstructed and not permeable, because the mind does not have simultaneous thoughts and objects do not appear all at once.