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

[102] When Balak, the king of the Moabites, who had from his ancestors a friendship and league with the Midianites, saw how great the Israelites were grown, he was much affrighted on account of his own and his kingdom's danger; for he was not acquainted with this, that the Hebrews would not meddle with any other country, but were to be contented with the possession of the land of Canaan, God having forbidden them to go any farther ¹ So he, with more haste than wisdom, resolved to make an attempt upon them by words; but he did not judge it prudent to fight against them, after they had such prosperous successes, and even became out of ill successes more happy than before, but he thought to hinder them, if he could, from growing greater, and so he resolved to send ambassadors to the Midianites about them. Now these Midianites knowing there was one Balaam, who lived by Euphrates, and was the greatest of the prophets at that time, and one that was in friendship with them, sent some of their honorable princes along with the ambassadors of Balak, to entreat the prophet to come to them, that he might imprecate curses to the destruction of the Israelites. So Balsam received the ambassadors, and treated them very kindly; and when he had supped, he inquired what was God's will, and what this matter was for which the Midianites entreated him to come to them. But when God opposed his going, he came to the ambassadors, and told them that he was himself very willing and desirous to comply with their request, but informed them that God was opposite to his intentions, even that God who had raised him to great reputation on account of the truth of his predictions; for that this army, which they entreated him to come and curse, was in the favor of God; on which account he advised them to go home again, and not to persist in their enmity against the Israelites; and when he had given them that answer, he dismissed the ambassadors.