Then how do you handle the contradiction you have created with your stance?
The writings in the OT were in light of what people could understand at that time. God was slowly revealing self to them. Jesus is the fullest revelation of God that we have. So, you cannot hold writings such as you use to be as accurate as those about Jesus. With Jesus we have a fuller understanding of God and thus his words in the NT are to be adhered to, especially when they contradict the OT.
I do not believe Jesus would approve killing another. I do believe he would expect us to calmly talk to that person. Hostile actions only breed hostile actions in the carnal world. Jesus did not harm anyone in the two instances I can think of where he was in danger.
Perhaps you do not believe that God revealed himself to mankind slowly with the fullest revelation being that of the life of Christ.
I know you don't realize it, but the implications of what you are saying here mirror one of the great early heresies the Church battled- Marcionism.
The words of the Old Testament are the Words of GOD. It is great evil to repudiate them.
The only writings of the Old Testament that you get to NOT abide by are the ones which the New Testament identifies as not applicable to us (ceremonial law, Jewish civil laws, etc...)
If you repudiate the Old Testament then you have no precedent for musical instrumentation in worship, you have no permission to fight for your country, no reason to think that Jesus IS the Messiah, no indication that God blesses and curses nations, etc...
As a matter of fact when you repudiate the Old Testament you eliminate about two thirds of the Word of God.
This is a HORRIBLE practice.
Jesus does not have to say in the New Testament that it is OK to do something he already said was OK to do in the Old Testament. The only time it is not OK to do something that he said was OK to do in the OT is when he says in the New Testament that it is now NOT ok.