The answer really has several parts.
1. Because God made us, he can do what he wants with us.
Isaiah 64:8 But now, O LORD, thou art our father; we are the clay, and thou our potter; and we all are the work of thy hand.
Jeremiah 18:6 O house of Israel, cannot I do with you as this potter? saith the LORD. Behold, as the clay is in the potter‘s hand, so are ye in mine hand, O house of Israel.
Romans 9:21 Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
Deuteronomy 32:39 See now that I, even I, am he, and there is no god with me: I kill, and I make alive; I wound, and I heal: neither is there any that can deliver out of my hand.
2. We are all condemned to death because Adam disobeyed God and brought sin and death upon us all.
Romans 5:12 Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
Ezekiel 18:4... the soul that sinneth, it shall die.
Romans 6:23 For the wages of sin is death...
We all sin and have no right to either quality or length of life. We will all die whether by accident, disease, old age, natural disasters or at the hand of our fellow man.
Luke 13:4 Or those eighteen, upon whom the tower in Siloam fell, and slew them, think ye that they were sinners above all men that dwelt in Jerusalem? 5 I tell you, Nay: but, except ye repent, ye shall all likewise perish.
This life is transient and unless we repent and live by God’s commandments it is lived in vain, so its length or mode of termination matters not one jot.
Psalms 49:20 Man that is in honour, and understandeth not, is like the beasts that perish.
If we believe God and change the way we live he will reward us with everlasting life when Jesus returns.
3. Nations are punished for their wickedness and it is on this basis that God has men, women and children destroyed.
Jeremiah 18:1 The word which came to Jeremiah from the LORD, saying, 2 Arise, and go down to the potter’s house, and there I will cause thee to hear my words. 3 Then I went down to the potter’s house, and, behold, he wrought a work on the wheels. 4 And the vessel that he made of clay was marred in the hand of the potter: so he made it again another vessel, as seemed good to the potter to make it. 5 Then the word of the LORD came to me, saying, 6 O house of Israel, cannot I do with you as this potter? saith the LORD. Behold, as the clay is in the potter’s hand, so are ye in mine hand, O house of Israel. 7 At what instant I shall speak concerning a nation, and concerning a kingdom, to pluck up, and to pull down, and to destroy it; 8 If that nation, against whom I have pronounced, turn from their evil, I will repent of the evil that I thought to do unto them. 9 And at what instant I shall speak concerning a nation, and concerning a kingdom, to build and to plant it; 10 If it do evil in my sight, that it obey not my voice, then I will repent of the good, wherewith I said I would benefit them.
When nations turn from God and worship idols they do all kinds of evil to their fellow men in the sight of God. With the flood God destroyed men, women and children because the earth was filled with violence.
Genesis 6:13 And God said unto Noah, The end of all flesh is come before me; for the earth is filled with violence through them; and, behold, I will destroy them with the earth.
Sodom and Gomorrah were destroyed because of their collective sin.
Genesis 13:13 But the men of Sodom were wicked and sinners before the LORD exceedingly.
Genesis 18:20 And the LORD said, Because the cry of Sodom and Gomorrah is great, and because their sin is very grievous;
If there had been just 10 righteous people in Sodom it would not have been destroyed.
Genesis 18:32 And he said, Oh let not the Lord be angry, and I will speak yet but this once: Peradventure ten shall be found there. And he said, I will not destroy it for ten’s sake.
In the time of Abraham the sin of the Canaanites had not come to the full. They had a further 400 years of wickedness before God gave their land to Israel.
Genesis 15:16 But in the fourth generation they shall come hither again: for the iniquity of the Amorites is not yet full.
God told Israel to utterly destroy the Canaanites because if they didn’t they would lead Israel into idolatry and wickedness. The women were just as idolatrous as the men and the children would grow up to be the same.
Deuteronomy 7:2 And when the LORD thy God shall deliver them before thee; thou shalt smite them, and utterly destroy them; thou shalt make no covenant with them, nor shew mercy unto them: 3 Neither shalt thou make marriages with them; thy daughter thou shalt not give unto his son, nor his daughter shalt thou take unto thy son. 4 For they will turn away thy son from following me, that they may serve other gods: so will the anger of the LORD be kindled against you, and destroy thee suddenly.
What would happen was graphically portrayed at Baalpeor
Numbers 25:1... the people began to commit whoredom with the daughters of Moab. 2 And they called the people unto the sacrifices of their gods: and the people did eat, and bowed down to their gods. 3 And Israel joined himself unto Baalpeor: and the anger of the LORD was kindled against Israel... 9 And those that died in the plague were twenty and four thousand.
Before his death Joshua warned Israel:
Joshua 23:11 Take good heed therefore unto yourselves, that ye love the LORD your God. 12 Else if ye do in any wise go back, and cleave unto the remnant of these nations, even these that remain among you, and shall make marriages with them, and go in unto them, and they to you: 13 Know for a certainty that the LORD your God will no more drive out any of these nations from before you; but they shall be snares and traps unto you, and scourges in your sides, and thorns in your eyes, until ye perish from off this good land which the LORD your God hath given you.
Israel didn’t utterly destroy them and the Canaanites that were left did exactly what God had said they would do.
The books of Judges, Samuel, kings and Chronicles record the downfall of the nation contaminated by the idolatry of the Canaanites.
Because of this, men, women and children of Israel were in turn destroyed and sent into captivity. When their descendents returned they were cured of Idolatry but they again fell into wickedness. They murdered the prophets that God sent to warn them.
Jesus says to them.
Matthew 23:32 Fill ye up then the measure of your fathers.
They filled up the measure of the sins of their forebears by murdering their messiah and persecuting his church. As a consequence they were destroyed in their thousands, men, women and children and removed from the land in AD70. Their descendents have suffered persecution for almost 2000 years in fulfilment of Christ’s prophecy.
Luke 21:24 And they shall fall by the edge of the sword, and shall be led away captive into all nations: and Jerusalem shall be trodden down of the Gentiles, until the times of the Gentiles be fulfilled.
We have to recognise that when God commands men to kill it is a sin not to. He has the authority over his creation to destroy whom he will. God is a righteous judge who looks upon the hearts.
4. In the Law ‘Thou shalt not kill’ refers to the act of premeditated murder.
Under the Law a murderer was to be put to death by the ‘revenger of blood’ that is - a close relative of the victim.
5. The killing of the murderer was commanded by God.
Numbers 35:19 The revenger of blood himself shall slay the murderer: when he meeteth him, he shall slay him... 33 So ye shall not pollute the land wherein ye are: for blood it defileth the land: and the land cannot be cleansed of the blood that is shed therein, but by the blood of him that shed it.
6. A Christian is not under the Law of Moses.
He is commanded to love his enemies and not to exact revenge, but leave it in the hand of God.
Romans 12:19 Dearly beloved, avenge not yourselves, but rather give place unto wrath: for it is written, Vengeance is mine; I will repay, saith the Lord.
A Christian sets no store by this life, whether long or short; he looks for that life which is to come by resurrection in the kingdom of God.
John 12:25 He that loveth his life shall lose it; and he that hateth his life in this world shall keep it unto life eternal.
7. A person’s life should not be evaluated by its quality or length but by whether it is lived by the commandments of God. Wickedness is only endured by God in order to save the righteous.
Back to the potter.
Romans 9:22 What if God, willing to shew his wrath, and to make his power known, endured with much longsuffering the vessels of wrath fitted to destruction: 23 And that he might make known the riches of his glory on the vessels of mercy, which he had afore prepared unto glory, 24 Even us, whom he hath called, not of the Jews only, but also of the Gentiles?
The vessels of mercy are prepared by the foreknowledge of God on the basis of how he knows that they will react to his message. Those who will not live by God’s commandments are suffered by God and when necessary destroyed in the light of the same foreknowledge.
I hope you have found this helpful.
May God bless you,