大般涅槃經集解 5.118

5.118

案僧亮曰：善已今施，必成佛福田也。涅槃難了，若檀行成就，自當了也。道慧記曰：純陀迹未善解設供之法，故携文殊去也。

Sengliang comments: Having rejoiced, his present giving will certainly become the Buddha's field of merit. Nirvāṇa is difficult to comprehend; if the practice of giving is perfected, one will naturally comprehend it. Daohui notes: As for his external traces, Cunda did not yet fully understand the ritual method of preparing an offering, so he took Mañjuśrī along with him.