Meditation Sutra
At one time Śākyamuni Buddha was staying on Vulture Peak together with one thousand two hundred and fifty monks and thirty-two thousand bodhisattvas. Incited by Devadatta, Ajātaśatru imprisoned King Bimbisāra and later Queen Vaidehī too, because she brought food and drink to the king. In utter despair she requested the Buddha to help her. The Buddha immediately sent two disciples to her, and afterward himself appeared in the prison where she was confined. As she wished to be born in a land with no sorrow, he showed her many buddha lands to let her make her choice. To the Buddha’s satisfaction, she chose the Pure Land of Amitāyus. Vaidehī was thus able to visualize the Pure Land through the Buddha’s power. For the sake of later generations, the Buddha expounded a method of contemplation in thirteen stages (sections 9–21)
The next three contemplations are of the nine categories of Pure Land aspirants in three grades (sections 22–30). The highest grade corresponds to the fourteenth contemplation, the middle grade to the fifteenth, and the lowest grade to the sixteenth. Each grade is divided into three levels: highest, middle, and lowest.
When the above discourse was delivered, Vaidehī attained spiritual awakening and her five hundred court ladies aspired to enlightenment. After Śākyamuni and his attendants returned to Vulture Peak, Ānanda related the whole sutra to the assembly.
Read the full sutra here: https://www.bdk.or.jp/document/dgtl-dl/dBET_ThreePureLandSutras_2003.pdf