Adam Clarke on Joshua 9:14

The men took of their victuals - This was done in all probability in the way of friendship; for, from time immemorial to the present day, eating together, in the Asiatic countries, is considered a token of unalterable friendship; and those who eat even salt together, feel themselves bound thereby in a perpetual covenant. But the marginal reading of this clause should not be hastily rejected.

And asked not counsel at the mouth of the Lord - They made the covenant with the Gibeonites without consulting God by Urim and Thummim, which was highly reprehensible in them, as it was a state transaction in which the interests and honor of God their king were intimately concerned.