俱舍論記 17.71

17.71

「四俱轉者至勤策律儀」者，明四業道與思俱轉。四俱轉者，謂惡、無記心現在前位得近住等戒，但有身三、語一業道俱轉。

Regarding "Four functioning simultaneously up to the restraint of a novice": this clarifies four courses of action functioning simultaneously with volition. 'Four functioning simultaneously' means that at the stage when an unwholesome or indeterminate mind is present and one obtains the precepts of upavāsa and the like, only three bodily and one verbal course of action function simultaneously.