I attended a Christian college with an Anabaptist-pacifist establishment. Coming from a military family, reflecting on scripture, I’ve thought long and hard on the subject. I can give very solid arguments why the New Testament does not demand pacifism.
The original English bible translations (Tyndale to King James) of the 1500s were done at a time before extensive knowledge of Hebrew. English has changed a bit since then too—and few in those generations questioned that the Bible allows killing in war, self-defense, and lawful executions. Given that in the very same book (Exodus) a few chapters away from the Decalogue, God commands warfare in certain conditions and executions, you’d think any common-sense interpreter would understand that the “thou shalt not kill” command is not without exceptions.
Unfortunately, poor biblical interpretation—using ONLY the New Testament (without sufficient reliance on the Old Testament) led certain radical Christian sects (the Anabaptists in Europe, and the Quakers in the UK) to conclude foolish pacifism was commanded for Christians.
So the issue was bigger than just a mistranslation of “teer.”
Fortunately pacifist Christian sects have always been a small minority of Christians (most were persecuted and chased out of Europe to the America.) Unfortunately, their ideas still influence people, especially on the liberal side of the political spectrum.
The 1960s—for those who didn’t want to fight in a war to protect Asians in Vietnam—pacifism was used as an ideal by the anti-war movement—which given that the leadership were Marxists, I believe was inauthentic pacifism.
I had professors,roommates and friends in college who were pacifists (Mennonites) and they were sincere, even though sincerely wrong. Jesus said “love your enemies” so this is where they get this.
Sound Christian Bible interpretation though tensions Jesus’ words, with the Old Testament, which He upheld. Christian pacifists really cannot come to grips with the military action and death penalty laws commanded by God for the Jews in the Old Testament.
They have to assume a radical break between Old and New Testaments—which is not consistent with there being only one God who inspired both.
Mainstream Protestant, Catholic, and Eastern Orthodox Christianity though does accept that killing is sometimes just—which is how the concept of “Just War” principles developed.
Saint Jerome reputedly was the foremost biblical scholar of his day, and he used “Non occides,” in his 4th-Century Vulgate Latin transliteration.