The mahayana Buddhism is full of excellent teachings and stories
the topic here refers to the Sutra of Perfect Enlightenment , Lankavatara Sutra and Shurangama Sutra
This is the 3 Mahasattva Q & A sutra on the nature of mind
Sutra of Perfect Enlightenment was emphasized in Korean Zen Buddhism
while Shurangama sutra and Lankavatara in China