Yes god implemented it...and many innocents have been sentenced to death. The death penalty is wrong and it is wrong because man makes mistakes.
Then, according to you, God must have made a mistake when He implemented it.
Did you know that God also implemented a penalty for bearing false witness? The penalty was that whatever the penalty would have been for the person witnessed falsely against, that was the penalty for the false witness. Many of the death penalty convictions that have later been overturned were because overzealous prosecutors wanted to get a conviction no matter what the truth was.
How far do you think our prosecutors would be willing to push a trial with flimsy evidence, if we held them to that standard--where they would suffer the death penalty if they pushed for conviction falsely? The death penalty isn't what's wrong (and we know this because, as you agreed, God implemented it, and we don't believe God makes mistakes). It's our implementation of it, and sometimes our lack of implementation.
And please do not start on about dna evidence...that evidence is only as good as the person who reads the results...and they have made mistakes. Unless you can prove 100% which is next to impossible to do the death penalty should not be on the table. And read gods laws again many of them seem more like the laws and beliefs of the people living in that time period tha the laws of all knowing, all merciful, all loving god. I know a girl who was raped and she does not go to church or worship anymore. She told me that god is supposed to be our father, what father sits by and watches his child be raped. She's got a point, I am a father and if I saw my daughter being raped I would kill the man no ands ifs or buts. The point is man it is next to impossible to prove anyone guilt 100%
What was the penalty supposed to be for rape? God implemented the death penalty. That means that her heavenly father was not "sitting by and watching His child be raped." Instead, He said her rapist should be punished with his life--JUST LIKE YOU SAID YOU WOULD DO! You have a proper sense of justice regarding your daughter's rapist, but why aren't you willing to carry it out?
Deut 19:15 A single witness may not testify against another person for any trespass or sin that he commits. A matter may be legally established only on the testimony of two or three witnesses. 16 If a false witness testifies against another person and accuses him of a crime, 17 then both parties to the controversy must stand before the Lord, that is, before the priests and judges who will be in office in those days. 18 The judges will thoroughly investigate the matter, and if the witness should prove to be false and to have given false testimony against the accused, 19 you must do to him what he had intended to do to the accused. In this way you will purge the evil from among you. 20 The rest of the people will hear and become afraid to keep doing such evil among you.
There was also a penalty for "man-stealing" or what we call, ironically based on your example, "kidnapping". That penalty was death.
And I'm not necessarily a big fan of DNA evidence, at least not by itself, but it is allowed for in the Old Testament law--one example is the above citation, where the judges will "thoroughly investigate the matter". But the purpose for such harsh penalty for perjury (death in many cases), is in vs 19 and 20: 1. you will purge the evil from among you, and 2. the rest of the people will be afraid to do similar evil. The evil in our world has continued to grow. I think it is partly from a lack of adherence to the things God told us would "purge" evil from among us.