MN 121 Cūḷasuññata Sutta: The Shorter Discourse on Emptiness
14 pages
The Buddha describes his own meditation on emptiness and tells Ānanda how a meditator can descend into emptiness herself through seclusion and wise attention.
For a more detailed, comparative analysis including a practice guide, see Bhikkhu Analayo’sarticle: “Gradual Entry into Emptiness”.