Deuteronomy 13:15

Thou shalt surely smite the inhabitants of that city with the edge of the sword, destroying it utterly, and all that is therein, and the cattle thereof, with the edge of the sword.

The verse belongs to Moses's rehearsal given before Israel crossed the Jordan into the promised land, recalling the wonderful works God had done for His people and some of the chief laws connected with Israel. It recounts Israel's experiences and God's guidance during forty years of wilderness wandering as one constant appeal to serve the Lord and to turn away from the sins that wrecked the other nations, in which alone lay Israel's greatness and continuance. Its purpose is to bring those lessons to remembrance and to impress the sacred import of God's holy law and the necessity of keeping it. The chapter presents a good test by which to try prophets, warning against false prophets even when they work signs and wonders. The standard by which they are to be tested is the law of God, so that any prophet who leads away from that law is false. The command to smite the inhabitants of the idolatrous city utterly with the edge of the sword, destroying it and all therein and the cattle thereof, shows the wonderful working and superiority of the laws God gave to Israel amid the conditions surrounding them.

Breaking the first two precepts of God's law brings the transgressor under the curse, and the judgment pronounced upon the city, all within it, and its cattle records the consequence of violating those commandments. The passage affixes death at the hand of the civil magistrate to the precepts of the moral law, the same penalty affixed to violation of the Sabbath. This was because the moral law embracing the Sabbath formed part of the civil code of the Hebrew nation, and as such penalties to be inflicted by the magistrate were annexed to it. Those penalties inflicted by the magistrate shadowed forth the final retribution of the ungodly. That civil penalty was suspended by the Saviour's decision that only those without sin should cast the first stone, yet the real penalty of the law, the wages of sin, was not set aside nor the violated precept weakened. A sinless Being will yet arise to punish men when the hailstones of His wrath desolate the earth.

The directions in this passage supplied what the Jewish leaders hoped to use to condemn the apostles for sorcery and to put them to death in response to the miracle and the apostles' teaching.