What was a classic pick-up line in Israel? “So, you’re from Ai? How do spell that?”
This worked as well as modern pick-up lines do.
Moving on…Joshua 8 addresses the conquest of Ai after the failure at Ai. The contrast here is mainly seen as God at work in the obedient after seeing God’s refusal to bless the people due to Achan’s sin.
That’s a valid lesson. God honors obedience and judges sin. I think it’s a little simplistic to then apply this over and claim that the obedient always have things go right. That is not supported in the rest of Scripture.
There is also this: the original attempt to capture Ai involved a certain disinterest from the people. Just a few were needed, the spies said, so just a few went.
God’s work by His people is never a matter for just a few.
Also worth noting is the use of the strategy of ambush at Ai. Not because Ambush is a new concept. Because God uses the situation to turn what the people of Ai thought was the weakness of His people into the Israelite’s victory.
Give your failures to God. Let Him use those. It may require a vulnerability that you are thoroughly uncomfortable with, but it’s a necessity.