Having delivered the ultimate secret, Krishna places a strict security protocol around it. He instructs Arjuna that this highly confidential knowledge (idaṁ) must never, ever be spoken (na kadācana vācyaṁ) to four types of people: 1) those who lack self-discipline or austerity (nātapaskāya), 2) those who have no devotion (nābhaktāya), 3) those who refuse to hear or serve (na cāśuśrūṣave), and 4) those who are deeply envious of Krishna as the Supreme Lord (na ca māṁ yo 'bhyasūyati).