Philo Judaeus De Virtutibus 69

[69] And then, looking upon Joshua, he exhorted him to approve himself a valiant man, and to be very strong in good and wise counsel, and to show himself the interpreter of his counsels, and to accomplish all his purposes with unyielding and vigorous decision. And he said thus much to him though he was not perhaps in need of any recommendation, but because he would not conceal their mutual affection for one another and for the whole people, by which he was spurred on as it were to lay bare before him what he thought would be advantageous.