Viśvarūpa, whom the demigods had engaged as their priest, instructed King Indra about the V Nārāyaṇa armor, which enabled Indra to conquer the demons. Viśvarūpa said, "If some form of fear arrives, a person should first wash his hands and legs and then perform ācamana by chanting this mantra: om apavitrah pavitro vā sarvāvasthām gato 'pi val yah smaret pundarikākṣam sa bahyabhyantarah sucih/ śrī-viṣṇu śrī-viṣṇu śrī-viṣṇu. Then he should touch kusa grass, sit gravely and silently facing north, and bind himself with the Nārāyaṇa coat of armor as follows:
First, while chanting the mantra composed of eight syllables—om namo nārāyaṇāya—beginning with the prānava, the syllable om, he should touch his hands to eight parts of his body, starting with the two feet and progressing systematically to the knees, thighs, abdomen, heart, chest, mouth, and head. Then he should chant the mantra in reverse, beginning from the last syllable ya, while touching the parts of the body in the reverse order. These two processes are known as as utpatti-nyāsa and samhara-nyāsa respectively.
Then the person should chant the mantra composed of twelve syllables—om namo bhagavate vāsudevāya. Preceding each syllable by the omkara, he should place the syllables of the mantra on the tips of his fingers, beginning with the index finger of the right hand and concluding with the index finger of the left. The four remaining syllables should be placed on the joints of the thumbs.
The chanter must then chant the mantra of six syllables—om viṣṇave namah. He should place the syllable om on his heart, the syllable vi on the top of his head, the syllable ṣa between his eyebrows, the syllable na on his tuft of hair, and the syllable ve between his eyes. The chanter of the mantra should then place the syllable na on all the joints of his body and meditate on the syllable ma as being a weapon. He should thus become the perfect personification of the mantra. Thereafter, adding visarga to the final syl- lable, ma, he should chant the mantra mah astrāya phat in all directions, beginning from the east. In this way, all directions will be bound by the protective armor of the mantra.
After finishing this chanting, the chanter should think himself qualitatively one with the Supreme Personality of Godhead, who is full in six opulences and is worthy to be meditated upon. Then he should chant the protective prayer to Lord Nārāyaṇa, the Nārāyaṇa-kavaca.