From where is "Niranjano nirakara, eko devo Maheswara" mantra taken from?

Question

Niranjano nirakara, eko devo Maheswara

From where is this mantra taken?

It seems to be related to the mahamritunjaya Mantra.

Answer 1

The "निरंजनो निराकार एको देवो महेश्वरः (Niranjano nirakara, eko devo Maheswara)" comes from an ancient Sanskrit tantric text named Shiva Swarodaya. This is found in 6th shloka of the text which contains total 395 shlokas:

देव्युवाच

तत्वमेव परं मूलं निश्चितं तत्त्ववादिभिः।

तत्त्वस्वरूपं किं देव तत्त्वमेव प्रकाशय।।5।।

Devi said:

The tattwas (elements) are the primal cause as ascertained by the exponents of the tattwas. O Lord, what is the nature of those elements? Kindly reveal that to me.

ईश्वर उवाच

निरंजनो निराकार एको देवो महेश्वरः।

तस्मादाकाशमुत्पन्नमाकाशाद्वायुसंभवः।।6।।

Ishwara said:

There is only one birthless and formless supreme existence from which manifests akasha (ether element), and from akasha comes vayu (air element) only when he manifests

The text can be found on Archive with name Swara Yoga with commentary and translation by Satyananda Saraswati and on wikibooks with Hindi translation