In the Veda the gods of the light and the highest heaven, Mithra and Varuna, are the guardians of truth and purity, the avengers and punishers of evil deeds. The invocation of Mithra in the Avesta, given above, showed us that the Arians of Iran recognised in this deity the spirit of purity, the inevitable avenger of injustice. With his all-penetrating eye he watches, not only over purity of body, but also over purity of soul. We may regard it as certain that the reform carried a long step forward the ethical impulse which lay in this conception of Mithra--a conception current on both sides of the Indus. This view is supported by the great importance which the Avesta ascribes to truthfulness, in the decisive value given to this virtue for the purity of the soul, and the identification of purity with truthfulness. As filth defiles the body, so, according to the Avesta, does a lie defile the soul. Lying and deception are the worst sins of which a man can be guilty. The ethical advance is obvious when the evil spirits are not merely regarded as doing harm to men, but it is emphatically stated that they deceive men, and a lie is the essence of the evil spirits. In the Avesta a part of them have simply the name of the spirits of deception, of the Druj. The suppliants of the true gods are called _Ashavan, i.e._ the true, the pure; the worshippers of the evil spirits are liars. The ideas of the Veda about the hosts of the spirits of ancestors, and the entrance of the good and pious into the heaven of light, are also current among the Arians of Iran. These the reform could not leave untouched. From the ethical characteristic which marks them, from the severe inculcation of a pure, true, active life, it proceeded to the idea of a sort of judgment on the souls after death. The detailed form in which this idea is presented to us in the Avesta will be given below.