首楞嚴義疏注經 7.159

7.159

同相也。此上異相為能有，生今同相為所有。異相本非有因而得生起，而為同相之因，斯即前文如是迷因，因迷自有。下文亦云「妄元無因，於妄想中立因緣性。」異既生同，同為能住，異為所住，故云住所住相。此住、所住元既無因，復何根本，斯則二相畢竟無住，故云了無根本。

This is the mark of sameness. The preceding mark of difference serves as that which can possess, giving rise to the present mark of sameness as that which is possessed. The mark of difference originally did not arise from having a cause, yet it serves as the cause for the mark of sameness. This is precisely what the previous text called 'such causes of confusion naturally exist because of confusion.' The text below also says, 'Falsehood originally has no cause; within false thinking the nature of causes and conditions is established.' Once difference has given rise to sameness, sameness serves as that which abides, and difference serves as that which is abided by; hence it is said, 'the marks abiding in what is abided by.' Since this abiding and what is abided by originally have no cause, what root could they have? Thus these two marks ultimately have no abiding; hence it is said, 'they have entirely no root.'