金光明經文句記 2.311

2.311

二、「觀心」下，明念佛。觀心既極，故能盡念佛不殺等種種功德皆等虛空。以深觀故，乃成疑念。

Second, from "contemplating the mind" down, explaining mindfulness of the Buddha. Since contemplation of the mind is pushed to the utmost, one is able to be completely mindful of the Buddha's various merits, such as non-killing, all being equal to empty space. Because the contemplation is profound, doubtful thoughts are thereby formed.