Enticers to idolatry, 1-5; however near to you, 6-8; are to be stoned to death, 9-11. Idolatrous cities are not to be spared, 12-18.
1 "If there arises among you a prophet, or a dreamer of dreams, and gives you a sign or a wonder, 2 And the sign or the wonder comes to pass, of which he spoke to you, saying, 'Let us go after other gods, which you have not known, and let us serve them,' 3 You shall not listen to the words of that prophet, or that dreamer of dreams. For the LORD your God proves you, to know whether you love the LORD your God with all your heart and with all your soul. 4 You shall walk after the LORD your God, fear him, keep his commandments, obey his voice, serve him, and cleave to him. 5 And that prophet, or that dreamer of dreams, shall be put to death, because he has spoken to turn you away from the LORD your God who brought you out of the land of Egypt and redeemed you from the house of bondage, to thrust you out of the way which the LORD your God commanded you to walk in. Thus you shall remove the evil from the midst of you.
6 "If your brother, the son of your mother, your son, your daughter, the wife of your bosom, or your friend, who is as your own soul, entices you secretly, saying, 'Let us go and serve other gods,' which you have not known—you, nor your fathers— 7 Namely, of the gods of the people who are around you, near to you, or far off from you, from one end of the earth even to the other end of the earth, 8 You shall not consent to him, nor listen to him, neither shall your eye pity him, neither shall you spare, neither shall you conceal him. 9 But you shall surely kill him. Your hand shall be first upon him to put him to death, and afterward the hand of all the people. 10 And you shall stone him with stones so that he dies, because he has sought to thrust you away from the LORD your God who brought you out of the land of Egypt from the house of bondage. 11 And all Israel shall hear, and fear, and shall no longer do any such wickedness as this among you.
12 "If you hear it said in one of your cities which the LORD your God has given you to dwell there, 13 That some men, the children of Belial, have gone out from among you and have withdrawn the inhabitants of their city, saying, 'Let us go and serve other gods,' which you have not known, 14 Then you shall inquire and make search and ask diligently. And behold, if it is truth and the thing certain that such abomination is wrought among you, 15 You shall surely smite the inhabitants of that city with the edge of the sword, utterly destroying it and all that is in it and its cattle with the edge of the sword. 16 And you shall gather all its plunder into the midst of its street, and shall completely burn the city and all its plunder with fire for the LORD your God. And it shall be a heap forever. It shall not be built again. 17 And there shall cleave nothing of the cursed thing to your hand, so that the LORD may turn from the fierceness of his anger, show you mercy, have compassion upon you, and multiply you, as he has sworn to your fathers, 18 When you listen to the voice of the LORD your God, to keep all his commandments which I command you this day, to do that which is right in the eyes of the LORD your God."
Matthew Henry Commentary - Deuteronomy, Chapter 13[➚]
[v.1] - This chapter opens up with a description of a false prophet. In fact, this whole chapter deals with such deceivers. Mark 13:22 says, "For false Christs, and false prophets will rise, and will show signs and wonders, to seduce, if it were possible, even the elect." Also, Matthew 7:15 says, concerning false prophets, "Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravening wolves." Matthew Henry spoke well of false prophets when he said, "False teachers encourage men to expect peace and salvation, without repentance, faith, conversion, and holiness of life."
[v.5] - Reference, 1st Corinthians 5:13.