大乘起信論廣釋卷第三．四．五 3.39

3.39

[Treatise:] Second is the characteristic of continuity [… down to …] because of non-interruption.
[Commentary:] Relying on the preceding discrimination of pleasing and non-pleasing objects, states of mind that perceive and recollect pain and pleasure arise; because they are constantly continuous, it is named 'characteristic of continuity'. That is, based on the previous thought discriminating pleasing objects, one gives rise to the perception of pleasant feeling; toward non-pleasing objects, one gives rise to the perception of painful feeling; frequently giving rise to thoughts, they appear in unbroken succession. This is precisely the continuity of thought in its own substance.