楞嚴經
In the "Śūraṅgama Sūtra", Mahāsthāmaprāpta tells of how he gained enlightenment through the practice of nianfo, or continuous pure mindfulness of Amitābha, to obtain samādhi. In the "Amitayurdhyana Sutra", Mahāsthāmaprāpta is symbolized by the moon while Avalokiteśvara is represented by the sun.