Josephus on Abraham

Now Abram, lacking a legitimate son of his own, adopted Lot, his brother Haran’s son, and his wife Sarai’s brother; and he left Chaldea when he was seventy-five years old, as God commanded him to go to Canaan, in which place he settled and left to his posterity. He was skillful, in terms of both understanding all things and persuading his listeners, and he was not mistaken about things that he sensed by instinct. On this account he began to have higher notions of virtue than others had, and he determined to renew and to change the opinion all men happened to have at that time concerning God. He was, therefore, the first who ventured to declare that there was one God, the sole creator of the universe; and as for other gods, if they contribute anything to the happiness of men, that each of them provides it only according to His imperative and not by means of their own power. He inferred these matters from the irregular phenomena that were visible both at land and at sea, as well as from those that happen to the sun and moon and to all the heavenly bodies; for he claimed that, were these bodies to have their own power, they would certainly attend to their own regular motions, but since they lack such regularity, it is clear that, in so far as they cooperate to our advantage, they do it not of their own abilities but through the power of He that commands them, to whom alone we should properly offer our honor and thanksgiving.