The people of Israel wanted to go and destroy their cities. They were hoping that Joshua and their leaders could renege on the terms of their treaty so that they could kill the Gibeonites as they were commanded by the Lord (Exodus 23:31; Joshua 9:26). When their leaders do not dissolve the covenant, the people begin to murmur and grumble. This grumbling recalls opposition to Moses (Exodus 15:24), except in this case the people are in the right: their leaders were never meant to make a treaty with the Gibeonites. Most likely the people were worried that this violation of the herem command (Joshua 6:17; cf. Deuteronomy 20:17) would result in covenant curse from the Lord, or perhaps withdrawal of his help.
17 And the people of Israel set out and reached their cities on the third day. Now their cities were Gibeon, Chephirah, Beeroth, and Kiriath-jearim.