Joshua 10:8

8. And the Lord discomfited them, etc It is uncertain whether the Lord anticipated the movement, and armed Joshua by his oracle, drawing him forth from Gilgal before he had taken any step, or whether he only confirmed him after he had made his preparations for setting out. It seems to me more likely that Joshua did not rush forth as soon as he was asked without consulting God, but at length, after being informed of his will, took up arms boldly and speedily. As he had lately been chastised for excessive facility, it is at least a probable conjecture that in this case of difficulty, he attempted nothing except in so far as he had a divine command. The Lord, therefore, had respect to the wretched Gibeonites when he did not allow them to remain destitute without the assistance of his people.

Joshua is made confident of victory in order that he may succor them; for God stimulates us more powerfully to the performance of duty by promising than by ordering. That which is here promised to one belongs to all, but for the sake of honoring Joshua, it is specially deposited with him that he may afterwards be the bearer of it to his army. For God does not speak from heaven indiscriminately to all sorts of persons, but confers the honor only on excellent servants and chosen prophets.

It is moreover worthy of notice that Joshua did not abuse the divine promise by making it an excuse for sluggishness, but felt the more vehemently inflamed after he was assured of a happy issue. Many, while they ostentatiously express their faith, become lazy and slothful from perverse security. Joshua hears that victory is in his hand, and that he may gain it, runs swiftly to battle. For he knew that the happy issue was revealed, not for the purpose of slackening his pace or making him more remiss, but of making him exert himself with greater zeal. Hence it was that he took the enemy by surprise.