Mahabharata Drona Parva Chapter 202:8

Mahabharata Drona Parva (Drona-vadha Parva) Chapter 202:8 And since his Phallic emblem is always supposed to be in the observance of the vow of Brahmacharya, and since he always gladden the world, therefore he is called Maheswara. The Rishis, the gods, the Gandharvas, and Apsaras, always worship his Phallic emblem which is supposed to stand upright. That worship maketh Maheswara glad. Indeed, Sankara (at such worship) becomes happy, pleased, and highly glad. And since with respect to the past, the future, and the present, that God has many forms, he is, on that account, called Vahurupa (many-formed). Possessed of one eye he blazeth forth in effulgence, or he may be regarded to have many eyes on every side of his body. And since, he possesseth the worlds, he is for that reason called Sarva. And since his form is like that of smoke, he is for that reason called Dhurjjati. And since those deities, viz., the Viswedevas are in him, he is for that reason called Viswarupa. And since three goddesses adore and have recourse to that Lord of the universe, viz., Firmament, Water and Earth, he is for that reason called Tryamvaka. And since he always increaseth all kinds of wealth and wisheth the good of mankind in all their acts, he is for that reason called Siva. He possesseth a thousand eyes, or ten thousand eyes, and hath them on all sides. And since he protecteth this vast universe, he is for that reason called Mahadeva. And since he is great and ancient and is the source of life and of its continuance, and since his Phallic emblem is everlasting, he is for that reason called Sthanu. And since the solar and the lunar rays of light that appear in the world are spoken of as the hair on the Three-eyed one, he is for that reason called Vyomakesa. And since, afflicting Brahma and Indra and Varuna and Yama and Kuvera, he destroyeth them ultimately, he is for that reason called Hara. And since, he is the Past, the Future, and the Present, and, in fact, everything in the universe, and since he is the origin of the past, the future, and the present, he is for that reason called Bhava. The word Kapi is said to mean supreme, and Vrisha is said to mean righteousness. The illustrious God of gods, therefore, is called Vrishakapi. And since Maheswara by means of his two eyes closed (in meditation), created through sheer force of will a third eye on his forehead, he is for that reason called the Three-eyed. Whatever of unsoundness there is in the bodies of living creatures, and whatever of soundness there is in them, represent that God. He is the wind, the vital airs called Prana, Apana (and the others) in the bodies of all creatures, including even those that are diseased. He who adoreth any image of the Phallic emblem of that high-souled God, always obtaineth great prosperity by that act. Downwards fiery, and half the body, that is auspiciousness is the moon. His auspiciousness is the moon. So also half his soul is fire and half the moon. His auspicious form, full of energy, is more blazing than the forms of the gods.