Śūraṅgama Sūtra

The Śūraṅgama Sutra is the Buddha's Śarīra, the Buddha's Dharmakāya (truth body).
Śarīra
https://en.wikipedia.org/wiki/%C5%9Aar%C4%ABra
Representative of the Dharma (bilingual)
https://www.book853.com/show.aspx?id=213&cid=79&page=5
You should pay special attention to every sentence of the "Shurangama Mantra" and do not treat it as an ordinary matter. It is a wonderful Dharma that is difficult to encounter in hundreds of thousands of kalpas. You may think that many people in the world explain the "Shurangama Mantra", but in fact, no one is explaining it.
Excerpted from "Simple Explanation of the Shurangama Sutra"
A Commentary by the Venerable Master Hsuan Hua
A Commentary by the Venerable Master Hsuan Hua
A Commentary by the Venerable Master Hsuan Hua
A Commentary by the Venerable Master Hsuan Hua
You often hear me preach about the three Decision Dharma of practice in Vinaya. That is so-called, concentrate one's heart is the precepts; from the precepts comes samadhi; and out of samadhi arises wisdom. This is named Triśikṣā (threefold training).

Heart of Shurangama Mantra
Om
ā nà lì
pí sir tí
pí lā bá sir lo tuó lì
pán tuó pán tuó nǐ
bá sir lā
bàng ní pàn
hǔ xīn dū lú yōng pàn
shā pó ho
https://youtu.be/HCphih_e40M?si=90B-FXRmmwWY4AKf

Śūraṅgama Sūtra volume 8
When they are on the verge of dying, but when the final warmth has not left their bodies, all the good and evil they have done in that life suddenly and simultaneously manifests.
