Joshua 7:4 So there went up thither of the people about three thousand men: and they fled before the men of Ai.
Joshua did not pray first, and the men also under his jurisdiction most likely did not pray too, or else, God would have given them a heads up by alerting them to the fact that a curse was resting upon the land, as He did with Rahab. And because of a lack of prayer, lives were lost, even though they did not participate in Achan’s sin. Their problem was not one of collusion to commit a crime.
Their issue was carelessness and presumption which led them to believe that just because the God of heaven had promised the land of Canaan they did not need to pray and ask Him for guidance. When God makes a promise, and begins to fulfill it in His own time and way, we should never conclude that devils would not try to interfere in some way or the other. In fact, it is a cardinal rule in the spiritual realm that whenever God is about to do great things for His people, the prince of darkness is also usually there, to contest every step of advance.
[2] According to the narrative, failure in a war could potentially be the result of an accursed thing, or an accursed person in the midst. This is a war now, and we should bear in mind that the thirty-six men never ever touched or even came close to the accursed thing, thus, they really did not know, and yet, here they are, being quite adversely affected while some of them have lost their lives in the process.
Joshua 7:5 And the men of Ai smote of them about thirty and six men: for they chased them from before the gate even unto Shebarim, and smote them in the going down: wherefore the hearts of the people melted, and became as water.
May God add His blessing to the study of His word. “Good night” and God bless!