Regarding the "buy a sword" quote, he said that to his disciples, and then later says to them that two swords are enough. The most common interpretation of this is that he needed to fulfill a prophecy, and also so as to get him arrested by the authorities for "leading a rebellion". Two swords are obviously not enough to win a rebellion, so it seems like the purpose of this wasn't to convert people through violence. There is a scene later where Peter famously cuts off one of the ears of the people sent to arrest Jesus, and then Jesus goes "enough of that!" and promptly heals the ear, and allows himself to be taken into custody peacefully.
Regarding the "not peace but a sword" quote, it's arguable that this is an obvious metaphor for ideological conflict.
Again, taken out of context, these verses can sound a lot more aggressive than the context would suggest.
Jesus also said things like "Those who live by the sword, die by the sword," "Turn the other cheek," and "Love your enemies".
So there's at least as many quotes from Jesus to support an argument for pacifism as there are to suggest otherwise. And arguably as those more pacifist quotes come from his core teachings like the Sermon on the Mount, it is more suggestive of his actual positions.
In the context of his overall ministry, and the fact that the Christian martyrs in general were known for their pacifism and willingness to sacrifice their own lives for what they believed in, I would argue that early Christianity spread more because of its non-violent tendencies, and the violence that its opponents inflicted on them. Of course, after Constantine's conversion and the politicization of the Church, things changed, and you could argue that Christianity became just another state religion that was spread by the sword in the same way all state religions arguably are. The Crusades also come to mind as an example of where Christianity was "spread by the sword", though one can make an argument that the Crusades were actually political actions disguised with religious rhetoric.
But I think you're trying too hard to find evidence that Jesus himself advocated physical violence, when most of the evidence is that he advocated a kind of pacifism, as well as an ideological revolution.
For me to say more would be a movement too far away from the original post, and so I will close by saying thank you for your criticism.
Not "rationality evangelism", which CFAR is doing already if I understand their mission. "Rational evangelism", which is what CFAR would do if they were Catholic missionaries.
If you believe in Hell, as many people very truly do, it is hard for Hell not to seem like the world's most important problem.
To some extent, proselytizing religions treat Hell with respect--they spend billions of dollars trying to save sinners, and the most devout often spend their lives preaching the Gospel (insert non-Christian variant).
But is Hell given enough respect? Every group meets with mixed success in solving its problems, but the problem of eternal suffering leaves little room for "mixed success". Even the most powerful religions are stuck in patterns that make the work of salvation very difficult indeed. And some seem willing to reduce their evangelism* for reasons that aren't especially convincing in the face of "nonbelievers are quite possibly going to burn, or at least be outside the presence of God, forever".
What if you were a rationalist who viewed Hell like certain Less Wrongers view the Singularity? (This belief would be hard to reconcile with rationalism generally, but for the sake of argument...) How would you tackle the problem of eternal suffering with the same passion we spend on probability theory and friendly AI?
I wrote a long thought experiment to better define the problem, involving a religion called "Normomism", but it was awkward. There are plenty of real religions whose members believe in Hell, or at least in a Heaven that many people aren't going to (also a terrible loss). Some have a stated mission of saving as many people as possible from a bad afterlife.
So where are they falling short?
If you were the Pope, or the Caliph, or the supreme dictator of some smaller religion, what tactics would you use to convince more people to do and believe exactly the things that would save them--whether that's faith or good works? Why haven't these tactics been tried already? Is there really much room for improvement?
Spreading the Word
This post isn't a dig at believers, though it does seem like many people don't act on their sincere belief in an eternal afterlife. (I don't mind when people try to convert me--at least they care!)
My main point: It's worth considering that people who believe in Very Bad Future Outcomes have been working to prevent those outcomes for thousands of years, and have stumbled upon formidable techniques for doing so.
I've thought for a while about rational evangelism, and it's surprisingly hard to come up with ways that people like Rick Warren and Jerry Lovett could improve their methodology. (Read Lovett's "contact me" paragraph for the part that really impressed me.)
We speak often of borrowing from religion, but these conversations mostly touch on social bonding, rather than what it means to spread ideas so important that the fate of the human race depends on them. ("Raising the Sanity Waterline" is a great start, but those ideas haven't been the focus of many recent posts.)
I'm not saying this is a perfect comparison. The rationalist war for the future won't be fought one soul at a time, and we won't save anyone with a deathbed confession.
But cryogenic freezing does exist. And on a more collective level, convincing the right people that the far future matters could be a coup on the level of Constantine's conversion.
CFAR is doing good things in the direction of rationality evangelism. How can the rest of us do more?
Living Like We Mean It
This movement is going places. But I fear we may spend too much time (at least proportionally) arguing amongst ourselves, when bringing others into the fold is a key piece of the puzzle. And if we’d like to expand the flock (or, more appropriately, the herd of cats), what can we learn from history’s most persuasive organizations?
I often pass up my chance to talk to people about something as simple as Givewell, let alone existential risk, and it's been a long time since I last name-dropped a Less Wrong technique. I don't think I'm alone in this.**
I've met plenty of Christians who exude the same optimism and conviviality as a Rick Warren or a Ned Flanders. These kinds of people are a major boon for the Christian religion. Even if most of us are introverts, what's stopping us from teaching ourselves to live the same way?
Still, I'm new here, and I could be wrong. What do you think?
* Text editor's giving me some trouble, but the link is here: http://www.relevantmagazine.com/god/practical-faith/evangelism-interfaith-world
** Peter Boghossian's Manual for Creating Atheists has lots to say about using rationality techniques in the course of daily life, and is well worth reading, though the author can be an asshole sometimes.