You haven't read the old testament, have you?
Anyone arrogant enough to reject the verdict of the judge or of the priest who represents the LORD your God must be put to death. Such evil must be purged from Israel. (Deuteronomy 17:12 NLT)
They entered into a covenant to seek the Lord, the God of their fathers, with all their heart and soul; and everyone who would not seek the Lord, the God of Israel, was to be put to death, whether small or great, whether man or woman. (2 Chronicles 15:12-13 NAB)
If a man still prophesies, his parents, father and mother, shall say to him, "You shall not live, because you have spoken a lie in the name of the Lord." When he prophesies, his parents, father and mother, shall thrust him through. (Zechariah 13:3 NAB)
Suppose you hear in one of the towns the LORD your God is giving you that some worthless rabble among you have led their fellow citizens astray by encouraging them to worship foreign gods. In such cases, you must examine the facts carefully. If you find it is true and can prove that such a detestable act has occurred among you, you must attack that town and completely destroy all its inhabitants, as well as all the livestock. Then you must pile all the plunder in the middle of the street and burn it. Put the entire town to the torch as a burnt offering to the LORD your God. That town must remain a ruin forever; it may never be rebuilt. Keep none of the plunder that has been set apart for destruction. Then the LORD will turn from his fierce anger and be merciful to you. He will have compassion on you and make you a great nation, just as he solemnly promised your ancestors. "The LORD your God will be merciful only if you obey him and keep all the commands I am giving you today, doing what is pleasing to him." (Deuteronomy 13:13-19 NLT)
If your own full brother, or your son or daughter, or your beloved wife, or you intimate friend, entices you secretly to serve other gods, whom you and your fathers have not known, gods of any other nations, near at hand or far away, from one end of the earth to the other: do not yield to him or listen to him, nor look with pity upon him, to spare or shield him, but kill him. Your hand shall be the first raised to slay him; the rest of the people shall join in with you. You shall stone him to death, because he sought to lead you astray from the Lord, your God, who brought you out of the land of Egypt, that place of slavery. And all Israel, hearing of this, shall fear and never do such evil as this in your midst. (Deuteronomy 13:7-12 NAB)
Suppose a man or woman among you, in one of your towns that the LORD your God is giving you, has done evil in the sight of the LORD your God and has violated the covenant by serving other gods or by worshiping the sun, the moon, or any of the forces of heaven, which I have strictly forbidden. When you hear about it, investigate the matter thoroughly. If it is true that this detestable thing has been done in Israel, then that man or woman must be taken to the gates of the town and stoned to death. (Deuteronomy 17:2-5 NLT)
One day a man who had an Israelite mother and an Egyptian father got into a fight with one of the Israelite men. During the fight, this son of an Israelite woman blasphemed the LORD's name. So the man was brought to Moses for judgment. His mother's name was Shelomith. She was the daughter of Dibri of the tribe of Dan. They put the man in custody until the LORD's will in the matter should become clear. Then the LORD said to Moses, "Take the blasphemer outside the camp, and tell all those who heard him to lay their hands on his head. Then let the entire community stone him to death. Say to the people of Israel: Those who blaspheme God will suffer the consequences of their guilt and be punished. Anyone who blasphemes the LORD's name must be stoned to death by the whole community of Israel. Any Israelite or foreigner among you who blasphemes the LORD's name will surely die. (Leviticus 24:10-16 NLT)
Suppose there are prophets among you, or those who have dreams about the future, and they promise you signs or miracles, and the predicted signs or miracles take place. If the prophets then say, 'Come, let us worship the gods of foreign nations,' do not listen to them. The LORD your God is testing you to see if you love him with all your heart and soul. Serve only the LORD your God and fear him alone. Obey his commands, listen to his voice, and cling to him. The false prophets or dreamers who try to lead you astray must be put to death, for they encourage rebellion against the LORD your God, who brought you out of slavery in the land of Egypt. Since they try to keep you from following the LORD your God, you must execute them to remove the evil from among you. (Deuteronomy 13:1-5 NLT)
But any prophet who claims to give a message from another god or who falsely claims to speak for me must die.' You may wonder, 'How will we know whether the prophecy is from the LORD or not?' If the prophet predicts something in the LORD's name and it does not happen, the LORD did not give the message. That prophet has spoken on his own and need not be feared. (Deuteronomy 18:20-22 NLT)
Then I heard the Lord say to the other men, “Follow him through the city and kill everyone whose forehead is not marked. Show no mercy; have no pity! Kill them all—old and young, girls and women and little children. But do not touch anyone with the mark. Begin right here at the Temple.” So they began by killing the seventy leaders. “Defile the Temple!” the Lord commanded. “Fill its courtyards with corpses. Go!” So they went and began killing throughout the city. (Ezekiel 9:5-7 NLT)
"You are my battle-ax and sword," says the LORD. "With you I will shatter nations and destroy many kingdoms. With you I will shatter armies, destroying the horse and rider, the chariot and charioteer. With you I will shatter men and women, old people and children, young men and maidens. With you I will shatter shepherds and flocks, farmers and oxen, captains and rulers. "As you watch, I will repay Babylon and the people of Babylonia for all the wrong they have done to my people in Jerusalem," says the LORD. "Look, O mighty mountain, destroyer of the earth! I am your enemy," says the LORD. "I will raise my fist against you, to roll you down from the heights. When I am finished, you will be nothing but a heap of rubble. You will be desolate forever. Even your stones will never again be used for building. You will be completely wiped out," says the LORD. (Jeremiah 51:20-26)
Anyone who is captured will be run through with a sword. Their little children will be dashed to death right before their eyes. Their homes will be sacked and their wives raped by the attacking hordes. For I will stir up the Medes against Babylon, and no amount of silver or gold will buy them off. The attacking armies will shoot down the young people with arrows. They will have no mercy on helpless babies and will show no compassion for the children. (Isaiah 13:15-18 NLT)
Cursed be he who does the Lords work remissly, cursed he who holds back his sword from blood. (Jeremiah 48:10 NAB)
I will make Mount Seir utterly desolate, killing off all who try to escape and any who return. I will fill your mountains with the dead. Your hills, your valleys, and your streams will be filled with people slaughtered by the sword. I will make you desolate forever. Your cities will never be rebuilt. Then you will know that I am the LORD. (Ezekiel 35:7-9 NLT)
My angel will go before you and bring you to the Amorites, Hittites, Perizzites, Canaanites, Hivites, and Jebusites; and I will wipe them out. (Exodus 23:23 NAB)
"All of you who are on the LORD's side, come over here and join me." And all the Levites came. He told them, "This is what the LORD, the God of Israel, says: Strap on your swords! Go back and forth from one end of the camp to the other, killing even your brothers, friends, and neighbors." The Levites obeyed Moses, and about three thousand people died that day. Then Moses told the Levites, "Today you have been ordained for the service of the LORD, for you obeyed him even though it meant killing your own sons and brothers. Because of this, he will now give you a great blessing." (Exodus 32:26-29 NLT)