When Israel had finished killing all the men of Ai in the fields and in the wilderness where they had chased them, and when every one of them had been put to the sword, all the Israelites returned to Ai and killed those who were in it. Twelve thousand men and women fell that day—all the people of Ai. For Joshua did not draw back the hand that held out his javelin until he had destroyed all who lived in Ai. But Israel did carry off for themselves the livestock and plunder of this city, as the LORD had instructed Joshua. So Joshua burned Ai and made it a permanent heap of ruins, a desolate place to this day. He impaled the body of the king of Ai on a pole and left it there until evening. At sunset, Joshua ordered them to take the body from the pole and throw it down at the entrance of the city gate. And they raised a large pile of rocks over it, which remains to this day. – Joshua 8:24-29
Luther writes:
Even though those Gentiles were worthy of death, nobody, not even the Israelites, was permitted to kill them unless prompted by a sure and evident command and word of God, so that the pronouncement should stand: “He who seizes the sword shall perish by the sword,” and again “Vengeance is Mine, and I shall repay,” and again “The Lord judges the peoples.” For He would gave life can rightfully take it away from those who have sinned against Him alone. Here, therefore, he used the Israelites for His service in order to execute His wrath through their hand.
MEMORY WORK – Shorter Catechism Q/A 45
Q. 45. Which is the first commandment?
A. The first commandment is, Thou shalt have no other gods before me.