大般涅槃經義記 8.123

8.123

下就人定，明一與二並非凡相，凡夫例惑，不能解知生死無常、涅槃常故。「以是」下結，以非凡夫所知義故，具二莊嚴方能問答。

Below, determining it in terms of persons, it clarifies that both the one and the two are not marks of ordinary beings, because ordinary beings are universally deluded and cannot understand or know the impermanence of saṃsāra and the permanence of nirvāṇa. The conclusion from "For this reason" onward states that because these are meanings not known to ordinary beings, only by possessing the two adornments can one question and answer.