Flavius Josephus, The Wars of the Jews
William Whiston, A.M., Ed.

[521] Now there was one of their commanders named Jacob, who offered to serve them readily upon that occasion, but had it in his mind to betray them. He went therefore from the village Alurus, wherein the army of the Idumeans were gotten together, and came to Simon, and at the very first he agreed to betray his country to him, and took assurances upon oath from him that he should always have him in esteem, and then promised him that he would assist him in subduing all Idumea under him; upon which account he was feasted after an obliging manner by Simon, and elevated by his mighty promises; and when he was returned to his own men, he at first belied the army of Simon, and said it was manifold more in number than what it was; after which, he dexterously persuaded the commanders, and by degrees the whole multitude, to receive Simon, and to surrender the whole government up to him without fighting. And as he was doing this, he invited Simon by his messengers, and promised him to disperse the Idumeans, which he performed also; for as soon as their army was nigh them, he first of all got upon his horse, and fled, together with those whom he had corrupted; hereupon a terror fell upon the whole multitude; and before it came to a close fight, they broke their ranks, and every one retired to his own home.