大乘百法明門論開宗義決 1.206

1.206

令顯睡眠非無體用者。釋前令字。由有實體令所依身不得自在。若無體性無此能故。此即標宗。

"Causing shows that sleep is not devoid of real substance and function": this explains the previous word "causing." Because it has real substance, it causes the physical body upon which it relies not to be self-governing. If it had no real nature, it would not have this capacity. This states the thesis.