Note: All Scripture quotations found in this article are from the text of the Authorized King James Version of the Bible.
The Lord was the first one who institute the death penalty in the first book of the Bible. The death penalty is given before the law, under the law and after the law. This below verse is before the law was given.
Genesis 9:6 "Whoso sheddeth man's blood, by man shall his blood be shed: for in the image of God made he man."
God Almighty has given man the responsibility to execute those that have murdered others.
Exodus 21:12 "He that smiteth a man, so that he die, shall be surely put to death."
As said before, Capital Punishment was given during the law in the Old Testament also.
Numbers 35:16 "And if he smite him with an instrument of iron, so that he die, he is a murderer: the murderer shall surely be put to death. 17 And if he smite him with throwing a stone, wherewith he may die, and he die, he is a murderer: the murderer shall surely be put to death. 18 Or if he smite him with an hand weapon of wood, wherewith he may die, and he die, he is a murderer: the murderer shall surely be put to death. 19 The revenger of blood himself shall slay the murderer: when he meeteth him, he shall slay him."
Some will argue that since it's given in the Old Testament, we are not under the law, so it's no longer in place, but Capital Punishment is also a New Testament command.
Romans 13:1 "Let every soul be subject unto the higher powers. For there is no power but of God: the powers that be are ordained of God. 2 Whosoever therefore resisteth the power, resisteth the ordinance of God: and they that resist shall receive to themselves damnation. 3 For rulers are not a terror to good works, but to the evil. Wilt thou then not be afraid of the power? do that which is good, and thou shalt have praise of the same: 4 For he is the minister of God to thee for good. But if thou do that which is evil, be afraid; for he beareth not the sword in vain: for he is the minister of God, a revenger to execute wrath upon him that doeth evil."
Not only did Paul approve of Capital Punishment, he also submitted to it himself in the book of Acts. Paul was the greatest Christian to ever live and he is also where we get our doctrine. We are to follow the Old Testament unless said otherwise in the New Testament.
Acts 25:11 "For if I be an offender, or have committed any thing worthy of death, I refuse not to die: but if there be none of these things whereof these accuse me, no man may deliver me unto them. I appeal unto Cæsar."
Capital Punishment is not only mentioned in the first book of the Bible, but also the very last book in the Bible.
Revelation 13:10 "He that leadeth into captivity shall go into captivity: he that killeth with the sword must be killed with the sword. Here is the patience and the faith of the saints."
Those that do not put Capital Punishment in place are responsible for defiling the entire land. How's that for an Environmental plan? Those that follow Capital Punishment are blessed by God.
Deuteronomy 19:11 "But if any man hate his neighbour, and lie in wait for him, and rise up against him, and smite him mortally that he die, and fleeth into one of these cities: 12 Then the elders of his city shall send and fetch him thence, and deliver him into the hand of the avenger of blood, that he may die. 13 Thine eye shall not pity him, but thou shalt put away the guilt of innocent blood from Israel, that it may go well with thee."
Numbers 35:30 "Whoso killeth any person, the murderer shall be put to death by the mouth of witnesses: but one witness shall not testify against any person to cause him to die. 31 Moreover ye shall take no satisfaction for the life of a murderer, which is guilty of death: but he shall be surely put to death. 32 And ye shall take no satisfaction for him that is fled to the city of his refuge, that he should come again to dwell in the land, until the death of the priest. 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. 34 Defile not therefore the land which ye shall inhabit, wherein I dwell: for I the LORD dwell among the children of Israel."
Truth is, if Capital Punishment was shown publicly like it was in the Old Testament with Israel, the crime rate would go down. Anyone that disagrees with Capital Punishment is simply humanistic in their thinking and ignores the word of God. Capital Punishment is just, Biblical and would make murderers think twice before going through with the sin. It is my personal belief that every murderer should be given the choice to accept Jesus Christ as their Saviour before put to death. God can forgive all sins, but most murderers are so evil and proud that they would turn their nose at the Gospel.