PRINCIPLES of LIFE of THE INDO ARYANS and THE IRANO ARYANS

Two ancient religions of The Aryans 

are Hindu and Zoroastrishm. 

Both teach the same principles of human behaviour.

HINDU 

Hindu/Vedic Religion is the religion of The Indo-Aryans. It teaches the principle of human behaviour named Tri Kaya Parisudha. The principle is interpreted into 3 basic human behaviors those should be purified. 
Tri Kaya Parisudha consists of :

Manacika

Wacika

Kayika

Manacika = Good Thoughts

Wacika = Good Words

Kayika = Good Deeds. 

Good Thoughts will underlie Good Words and from Good Words arisen Good Deeds. Basically, Good Words and Good Deeds come out from good mind. Good mind or Good Thoughts will lead human beings to say or to do any good things. 

From the principle of Tri Kaya Parisudha, the earliest should be controlled by human-beings is mind. Things those affect the mind should be awaken and should be controlled to build a mental or emotional stability. If this mind is muddled, especially thinking various matters, so the words and the deeds also become muddled. Since these two things muddled, human-beings will destruct and suffer. Vedic Scriptures teaches mankind to throw away the Evil and sinful deeds. To get away from rid of malice, mankind always do right things called dharma, by thinking, speaking, and doing the right things.
VEDA is the most principal religious book of Hindu Religion.

ZOROASTRISHM

Zoroastrishm is the religion of The Irano-Aryans. Zarathushtra the prophet was the founder of Zoroastrianism religion, brought messages for peace, progress, and prosperity on Earth and a blessful life beyond. His teachings to make life more living and divine. His message is based on the the Principle of human behaviour :

Good Thoughts 

Good Words

Good Deeds

It promotes the human mind and provokes its thinking faculty. It solves the complicated problem of Good and Evil by placing them in the human mind as teo opposing mentalities not entities. Good serves and promotes human society in an ecological sound world, while the Evil damages and retards society’s good progress. A human being endowed with a discriminating mind, is born free, to choose GOOD or EVIL.

To choose wisely good or evil things, it makes great responsibility for a human-being as an individual person. A person is good if the person chooses to think “Good Thoughts”, a person is good if the person speaks “Good Words”, and a person is good if the person performs “Good Deeds”. 

That is why all Zarathushtra’s teachings about Human Behaviour are based on Good Thoughts, Good Words, and Good Deeds. Teachings about human behavior of Zoroastrianism included in AVESTA, the most principal religious book of Zoroastrishm.