The ninth mandala (book) of the Rigveda is entirely devoted to:

The ninth mandala of the Rigveda is entirely devoted to Soma, the sacred plant, its juice, and the god of the drink.

About the ninth mandala:

• It contains 114 hymns, all addressed to "Soma Pavamana" ("Soma being purified").
• The hymns describe the pressing of the soma plant, the filtering of the juice through a woollen strainer, and its mixing with milk or water.
• They describe the effects of drinking soma: strength, inspiration, joy and a sense of immortality.
• The hymns of the ninth mandala were collected from different families of sages and placed together because they were used in the soma ritual.

About Soma:

• Soma was a plant whose juice was offered to the gods (especially Indra) and drunk by the priests in sacrifices.
• The soma sacrifice was one of the most important Vedic rituals.
• Soma was also worshipped as a god; he was later identified with the Moon.
• The plant is described as growing in the mountains, especially on Mount Mujavant.
• What was the soma plant?
• Its exact identity is unknown and is debated by scholars.
• Suggestions include the ephedra plant, a type of mushroom (the fly agaric), and others.
• In the Avesta of the ancient Iranians, a similar drink is called "haoma", which shows the shared origins of the Vedic and Iranian peoples.

Soma rituals:

• "Agnishtoma": a basic soma sacrifice.
• Large soma sacrifices were part of royal rituals.
• In the later period, substitutes were used, as the original plant became unavailable.

Other Rigvedic gods:

• Indra: the god of war and rain.
• Agni: the god of fire.
• Varuna: the guardian of cosmic order.

Why not the other options?

• ✗Agni, Indra and Varuna have hymns in several mandalas, but the ninth mandala is wholly devoted to Soma.