大乘起信論義記 2.78

2.78

釋疑中，惑者聞淨法不空，則謂同於情執之有。故釋云：無相可取也，是則不空不異於空。

In resolving doubt: when a confused person hears that pure phenomena are non-empty, they then take it to be identical to the existence of conceptual attachment. Therefore the explanation says: 'neither is there any mark that can be grasped'; thus non-emptiness is not different from emptiness.