Second Kings, we learn that Menahem, leader of the Israelites, smote all the people who refused to follow him and all the women therein that were with child he ripped up (2 Kings 15:16).
Later, in Hosea, we learn that because the land of Samaria rejected God, Samaria shall become desolate; for she hath rebelled against her God: they shall fall by the sword: their infants shall be dashed in pieces, and their women with child shall be ripped up (Hosea 13:16).
Hosea decided to carry out Gods vengeance on the people by killing the unborn babies carried by the heathen women. He promised to slay even the beloved fruit of their womb (Hosea 9:16).
It was God who killed all the unborn children on the planet (other than those of Noahs immediate family) when He drowned everyone with the Great Flood (Genesis 7:23).
And it was God who inflicted abortion on all the pregnant women when he rained fire and brimstone on Sodom and Gomorrah, killing everyone who lived therein (Genesis 19:24-25).
According to Deuteronomy, if a child is unruly and disobedient, we not only have the option of killing him, but it is mandatory that he be stoned to death (Deuteronomy 21:18-21). The same is true for a child who speaks to us with foul language (Exodus 21:17). Or a child who hits us (Exodus 21:15).
God will use fire, plagues and beasts to kill sinners (FYI WE ALL FREAKING SIN,) and what did he say "good" Christians will do? "Shall rejoice over them, and make merry, and shall send gifts to one another" (Revelation 11:10).
Please feel free to add.