From Zoroastrianism's Sacred Avesta: Yasna 31-32 of Ahunavaiti Gatha

Zoroaster was a prophet who lived in eastern lran around 1800 BC. The teachings that emerged from his visions of God have become known as Zoroastrianism. Zoroastrian theology’s main tenets include the existence of one God and the personal happiness or reward that is the natural outcome of using one’s free will to formulate good thoughts, good words and good deeds. Respecting all life, Zoroaster was himself a pure vegetarian and forbade all animal sacrifice. His universal philosophy is believed to have influenced Greek thought and major revealed religions of the world. The sacred scriptures of Zoroastrianism are collected mainly in Avesta.