They Do Not Incarnate Any More

Bhasmajabala Upanishad is an ancient Shaiva scripture written in the form a dialogue between Mahadeva Shiva and Sage Jabala. It deals with various Shaiva topics including the holy mantras of Shiva, rituals, rules for wearing sacred ash, Shiva puja, and the sanctity of the city of Kashi (Varanasi). In the below section, we read about the real nature of Lord Shiva and liberation of pashus (individual souls). 

[Mahadeva said:]

I, conjoint with Uma, am the Brahman!

I, conjoint with Uma, am the Pavana that sanctified all.

I, conjoint with Uma, am the Generator of the various dispositions of the mind.

I, conjoint with Uma, am the Generator of the Earth.

I, conjoint with Uma, am the Generator of fire.

I, conjoint with Uma, am the Generator of the Sun.

I, conjoint with Uma, am the Generator of Indra.

I, conjoint with Uma, am the Generator of Vishnu.

I alone am the Generator of the Moon, the Devas, the terrestrial, mid-ethereal and the celestial regions and all the other worlds.

I, conjoint with Uma, am the source of all that has been, that continues to be generated in various and variegated forms, and all that is yet to be.

I am the great Rishi, the Seer of Vedic mantras.

I am Rudra, transcending all the universe.

I do see Hiranyagarbha and other Prajapatis that are yet to come into existence.

I alone am the innermost Atman, that is immanent in all as the Antaratman [Indweller], the radiance of the Brahman, transcending which, transcending Me, there is naught else!

I alone am the transcendent Brahman that transcends the entire universe.

The world of persons, ignorant of the real nature of the Atman, on coming to realize Me alone attains the state of immortality and surmounts all misery. He, who, on coming to realize ME, remains in the attitude, “I am the Brahman alone” causes the disease of worldly existence to melt away. Hence I am known as Rudra [the Driver of the disease of worldly existence], who is the final resort of all. That reputed Rudra of the aspect of all, am I.

Knowing Me to be the Paramatman alone whence all creatures take their origin, through whom all these creatures continue to subsist, and whom they finally reach as their last resting place and get dissolved therein, one should resort to Me through upasana.

I alone am praised by all beings, and the Devas as well.

The wind wafts ouf of fear for Me. The Sun rises only out of fear of Me. Agni and Indra [discharge their duties] of out fear of Me.

I, conjoint with Uma, am alone the Controller of all and protector of all.

I am the Earth; I am the fire; I am air; I am time; I am the cardinal points; I am the Atman. In Me all things are established.

He who knows the Brahman himself attains the Parabrahman.

May Brahma, the Creator, be identical with Shiva unto me; may he be identical with Sadashiva too, OM!

I am the Ishvara of the universe that has no eyes and at the same time has eyes turned in all directions; that has no ears and has ears turned in all directions; that has no feet and at the same time has feet moving in all directions; that has no hands and at the same time has hands moving in all directions; that has no head and at the same time has heads in all directions.

I am Ishvara resorted to through the vidya mantras, that of the form of the vidya, composed of vidya, the Vishveshvara [Lord of the Universe] and devoid of dotage.

Having known me as of this character, the seeker after liberation is released from bonds of worldly existence.

For that reason I am the Liberator of pashus from the bonds of worldly existence (pasha).

All created beings down [from Brahma] down to the human beings and those that occupy intermediate positions are verily pashus.

Should any of these pashus have attained the balanced state of Samadhi, such persons endeavor to attain Me alone.

On attaining Me, they do not incarnate any more; they do not incarnate any more.

~Bhasmajabala Upanishad II:5-14 of the Atharvaveda.