One verse

Srimad Bhagavatam 6.8.4-6

6.8.4-6

श्रीविश्‍वरूप उवाच धौताङ्‌घ्रिपाणिराचम्य सपवित्र उदङ्‍मुख: । कृतस्वाङ्गकरन्यासो मन्त्राभ्यां वाग्यत: शुचि: ॥ ४ ॥ नारायणपरं वर्म सन्नह्येद् भय आगते । पादयोर्जानुनोरूर्वोरुदरे हृद्यथोरसि ॥ ५ ॥ मुखे शिरस्यानुपूर्व्यादोंङ्कारादीनि विन्यसेत् । ॐ नमो नारायणायेति विपर्ययमथापि वा ॥ ६ ॥

sri-visvarupa uvaca dhautanghri-panir acamya sapavitra udan-mukhah krta-svanga-kara-nyaso mantrabhyam vag-yatah sucih narayana-param varma sannahyed bhaya agate padayor janunor urvor udare hrdy athorasi mukhe sirasy anupurvyad omkaradini vinyaset om namo narayanayeti viparyayam athapi va

sri-visvarupah uvaca
Sri Visvarupa said
dhauta
having completely washed
anghri
feet
panih
hands
acamya
performing acamana (sipping a little water three times after chanting the prescribed mantra)
sa-pavitrah
wearing rings made of kusa grass (on the ring finger of each hand)
udak-mukhah
sitting facing the north
krta
making
sva-anga-kara-nyasah
mental assignment of the eight parts of the body and twelve parts of the hands
mantrabhyam
with the two mantras (om namo bhagavate vasudevaya and om namo narayanaya)
vak-yatah
keeping oneself silent
sucih
being purified
narayana-param
fully intent on Lord Narayana
varma
armor
sannahyet
put on oneself
bhaye
when fear
agate
has come
padayoh
on the two legs
janunoh
on the two knees
urvoh
on the two thighs
udare
on the abdomen
hrdi
on the heart
atha
thus
urasi
on the chest
mukhe
on the mouth
sirasi
on the head
anupurvyat
one after another
omkara-adini
beginning with omkara
vinyaset
one should place
om
the pranava
namah
obeisances
narayanaya
unto Narayana, the Supreme Personality of Godhead
iti
thus
viparyayam
the reverse
atha api
moreover
va
or

Visvarupa said: If some form of fear arrives, one should first wash his hands and legs clean and then perform acamana by chanting this mantra: om apavitrah pavitro va sarvavastham gato ’pi va/ yah smaret pundarikaksam sa bahyabhyantarah sucih/ sri-visnu sri-visnu sri-visnu. Then one should touch kusa grass and sit gravely and silently, facing north. When completely purified, one should touch the mantra composed of eight syllables to the eight parts of his body and touch the mantra composed of twelve syllables to his hands. Thus, in the following manner, he should bind himself with the Narayana coat of armor. First, while chanting the mantra composed of eight syllables [om namo narayanaya], beginning with the pranava, the syllable om, one 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 one should chant the mantra in reverse, beginning from the last syllable [ya], while touching the parts of his body in the reverse order. These two processes are known as utpatti-nyasa and samhara-nyasa respectively.