俱舍論記 5.58

5.58

「由何而得」者，問。「由加行得至亦成過去」者，答。是加行得。初唯現成，不得過去。亦不修未來，以無心故，要由心力方修未來。第二念等乃至未捨，亦成過去。

"Through what is it acquired?": this is a question. "Acquired through preliminary effort [...] also possesses the past": this is the answer. It is acquired through preliminary effort. Initially, it is possessed only as present; the past is not acquired. Nor does one cultivate the future: because it is mindless, one can only cultivate the future by the power of mind. In the second moment and subsequent ones until it is relinquished, one also possesses the past.