The gods, in the view of the Vedic poets, had a beginning; for they are described as the offspring of heaven and earth, or sometimes of other gods. This in itself implies different generations, but earlier gods are also expressly referred to in several passages. Nor were the gods regarded as originally immortal; for immortality is said to have been bestowed upon them by individual deities, such as Agni and Savitri, or to have been acquired by drinking soma. Indra and other gods are spoken of as unaging, but whether their immortality was regarded by the poets as absolute there is no evidence to show. In the post-Vedic view it was only relative, being limited to a cosmic age. The physical aspect of the Vedic gods is anthropomorphic. Thus head, face, eyes, arms, hands, feet, and other portions of the human frame are ascribed to them. But their forms are shadowy and their limbs or parts are often simply meant figuratively to describe their activities. Thus the tongue and limbs of the fire-god are merely his flames; the arms of the sun-god are simply his rays, while his eye only represents the solar orb. Since the outward shape of the gods was thus vaguely conceived, while their connection with natural phenomena was in many instances still evident, it is easy to understand why no mention is made in the Rigveda of images of the gods, still less of temples, which imply the existence of images. Idols first begin to be referred to in the Sutras. Some of the gods appear equipped as warriors, wearing coats of mail and helmets, and armed with spears, battle-axes, bows and arrows. They all drive through the air in luminous cars, generally drawn by horses, but in some cases by kine, goats, or deer. In their cars the gods come to seat themselves at the sacrifice, which, however, is also conveyed to them in heaven by Agni. They are on the whole conceived as dwelling together in harmony; the only one who ever introduces a note of discord being the warlike and overbearing Indra. To the successful and therefore optimistic Vedic Indian, the gods seemed almost exclusively beneficent beings, bestowers of long life and prosperity. Indeed, the only deity in whom injurious features are at all prominent is Rudra. The lesser evils closely connected with human life, such as disease, proceed from minor demons, while the greater evils manifested in Nature, such as drought and darkness, are produced by powerful demons like Vritra. The conquest of these demons brings out all the more strikingly the beneficent nature of the gods.