[Posala:]To one who reveals the past — unperturbed, his doubts cut through — who has gone to the beyond of all phenomena, I've come with a question. I ask the Sakyan about the knowledge  of one devoid of perception of forms, who has abandoned all the body, every body, who sees, within & without, 'There is nothing': How is he to be led further on?
[The Buddha:]The Tathagata, knowing directly all stations of consciousness,  knows for one stationed in them release & the steps leading there. Knowing directly the origin of nothingness to be the fetter of delight, one then sees there clearly. That's his genuine knowledge — the brahman who has lived to fulfillment.