So Joshua arose, and all the people of war, to go up to Ai: and Joshua chose out thirty thousand men, the mighty men of valor, and sent them forth by night.
Pink's understanding of why so many Israelites were engaged in such various ways in the reduction of Ai stressed the lesson that these events carry for Christians.  "God's predestination of an event does not render needless our use of means to bring it about."[12]  This principle has reinforcement in the N.T. in the event where Paul had already been assured by the Lord that no lives were to be lost in the forthcoming shipwreck, but when Paul noted the sailors about to abandon ship, he firmly stated that without them many lives would be lost (Acts 27:22-31).  Pink also pointed out that Joshua's knowledge of the devices of the enemy were turned to good account in this second effort to take Ai.  Joshua knew that the men of Ai would come out and chase them, as they did at first, and that proved to be the key to the winning strategy.  Concerning the Christian's war against Satan, "We are not ignorant of his devices"  (2 Corinthians 2:11).  Just as Joshua here turned the sure knowledge of what the king of Ai would do into a victory for Israel, Christians should be forewarned and ready to frustrate all of the devices of the Devil.