大乘起信論廣釋卷第三．四．五 3.39

3.39

論。二者相續相至不斷故　釋曰。依前分別愛非愛境而生苦樂覺念之心。常相續故名相續相。謂依前念分別愛境起樂受覺。於愛境起苦受覺。數數起念相續現前。此即自體念相續也。

[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.