Our best is not good enough

Read Joshua 9.

Instead of the victories at Jericho and Ai causing fear of the God of Israel, the surrounding kingdoms united to fight.  Some people never learn.  Some others are scared and act smart.  Say what you will, but the Gibeonites were cleaver.  Yes, they spent the rest of their lives as slaves but they figured it would be better to be slaves and alive than dead.

God's command was clear.  The inhabitants of the land were to be destroyed.  Period.  The Gibeonites dressed up and told a story of a great journey, when in fact they were next door neighbors.  Joshua violated the word of God when he accepted them, helped them, and then made a covenant of peace with them.  How did that happen?  Verse 14 gives the answer that Joshua "did not ask counsel of the LORD."

That was exactly the error he made in chapter 7.  He made these decisions as an owner, not as a steward  of what God gave to him.  A steward, or manager, always must represent what the owner wants done.  Yes, he asked good questions, but his best was not good enough. 
"There is a way that seems right to a man, but its end is the way to death." (Proverbs 14:12)

He needed spiritual insight and God's perspective in order to do what was right.

It seems after each victory there is a test.  Pride can get in the way, saying to us that we can handle the next challenge or the next decision on our own.  We can scarcely blame the devil for ignoring God's guidance in our lives.
Here is good counsel for all of us-
"Trust in the LORD with all your heart, and do not lean on your own understanding.  In all your ways, acknowledge him, and he will make straight your paths.  Be not wise in your own eyes; fear the LORD, and turn away from evil." (Proverbs 3:5-7)