From the Essence of Amarnatha yatra Phala article which is based on Bhringi Samhita of Skanda Purana,
Mritustaanagrasat sarvaan Devaabhi sa Vaasavaan,
Devaste mrityunaa grastaavya kulaahyabhavam Priye/
Sametya sharanam jaguh sharanyam Parameshwaram,
Tushtuvuh parama preetyaa Shankarah tamonaashranam/
- Mrityu tormented Devaas, headed by Indra, approached Parama Shiva for
refuge and protection and appealed as follows to the ever merciful
Shiva.
Namo niyati rupaaya tatwarupayate namah,
Mahattwaaya Devaaya Sukshma Tatwaayate namah/
Namomritaaya Devaaya Namomrita swarupine,
Mrityunjayaaya Devaaya bhuyo bhuyo namo namah/
- Our prayers to you Niyati Rupa, Tatwa Rupa, Mahattatwa, Sukshma
Tatwa, Amrita Rupa, Amrita Swarupine, Mrithyunjaya, Maha Deva, Bhuyo
bhuyo namyah. As the delegation of Devaas led by Indra commended as
above, Maha Deva was pleased and on his enquiry, Indra explained about
the constant threats posed by Mrityu to all of them:
Yatah sa mrityur nashyayenno seveccha balena hi,
Tatkurushwa Maha Deva bhaiktaanaamaarti naashana/
- Devadhideva! Do kindly show us a way out from the strangle hold of
Mrityu so that it should not overcome us and torment us; kindly ensure
that the desperation and constant threat to your Bhaktas like us be
terminated forthwith.
Shrutwaa Deva vachah soumyam Maheshah pratyuvaacha taan,
Mrityupaayam karishyaami sahadhwam kshanamuttamaah/
- Maha Deva realised the gravity of the problem and assured Devas of a solution soon
Griheetwaa shirastatra Haraschandra kalaam swayam,
Sampeedyav Devaanna vadanmrithyu bheshaja peedanaat/
Yaa nisrutaa chaiva tathaa dharaa seetatraa paarmika Priye,
Sauva bhutaa nede punyaa naamnaavaih Amaravati/
Ye bindavaschayutaa Devi Shariremrita bindavah,
Te bhasma rupataam prapyachyuscheshanataam gataah/
- Bhagavan himself adjusted the Chandra Kala on his head and pulled out a flow of Sacred River named Amaravati from his body. The River
materialised into chilled cool drops and as many drops of Amrita that
flowed turned out to take the shape of a hallowed Linga decorated with
Bhasma and that indeed was the Amara Natha Maha Deva Himself).
Premaateshaam Maha Devi Shivopidravataamagaat,
te drushtwaatu Shivam tatra dravibhutam Maheshwari/
- This was how Maha Deva got melted from the desperate cries of Devas to
save themselves from the clutches of Mrityu (That indeed was the
Origin of Amara Naatha Linga!).
Further Readings:
Many articles listed here also have some information from scriptures or early texts on the Amarnath Linga.