Son of Huineng: Bodhi has no trees, and it is not a stage in the mirror. There is nothing, so there is no dust.
These two sons are often regarded as the difference between gradual cultivation and epiphany.
They reflect the cultivation level of Shen Xiu and Huineng. Meixiu is still in the stage of wiping, and Huineng has realized the truth that both body and mind are empty.