Paul was talking there to the masters of slaves.
A quick clarification: my reference above was supposed to continue to verse 6 as well, in case I wasn't clear, even though I quoted both.
Well, this is not the biggest point, but I've interpreted the change of address differently. I've probably always viewed verses 2 to 6 (not to mention verses 7 and following) as addressed to the general audience of the letter, not just to the "masters" of verse 1. One reason is that the relatively longer address to "servants" (starting at 3:22) seems to me to be more thematically cohesive than a complementary address that would encompass 4:1-6.
The major relevance in this post would be that the admonitions of vv. 5-6 apply to the general audience, not only to such masters (and then to Christians in general, I suppose, instead of only to "masters" or their equivalent in a given society).
He was talking about how to talk to "outsiders" who may not have heard the gospel. Jesus was talking to abstinent leaders of the synagogue who had corrupted the word of God just as the Catholic Church leaders have.
Although I would not agree with the whole of this quotation, I do appreciate the difference in audience. I did notice, when I was quoting Colossians 4:5, that "them that are without" often seems to apply in heated discussion in the Religion Forum. Sometimes professing Christians address other professing Christians as if the Christianity of the latter is in question or in doubt.
Even more importantly, this is a public forum. "Them that are without" can be anywhere, and one important reason to watch our language is to be a good witness to the world. (It may be saying something that our Religion Forum has a lot of rules. Although I'd be wrenching it out of context to apply it directly, sometimes the discourse around here reminds me of Romans 2:24.)
You may also want to take my comments in context. I was simply pointing out that Jesus wasn't always so nicey, nicey when dealing with those how pervert what scripture says.
Yes, I did interpret your post as saying something like this, though I wanted some clarification before assuming that you meant something like this.
I say in response that part of "[walking] in wisdom" is knowing how to address one's intended audience.
I actually wasn't aware of the existence of this thread at all, let alone your post, until I searched for another recent post (which I found) that made a reference to "snakes" and "brood of vipers." So of course I found this thread as well.
I find this use of Matthew 23 interesting. For example, when I was looking at something else in the Religion Forum lately, I found an old post, a compilation of scriptural references in which Jesus and others address others as "fools."
Now, it's very nice that someone knows how to use a concordance, but one of those rules in this Religion Forum precludes our actually addressing other participants as "you fool" or "you snake." Thanks in some part to Matthew 5:22, I do not think that those rules stand between us and obeying Jesus.
I also do not view the apparent difference between Matthew 5:22 and that poster's long list as what some so-called skeptics would have us believe is a "biblical contradiction." One consideration: those who are tempted to call others "fools" based on apparent scriptual evidence should consider if they are like Jesus, or even Paul, before they go ahead and use similar language. Given the likely spiritual state of most of us, I would even guess that Matthew 5:22 applies more closely to most of us, and this rule edifies us more than it hurts. "Herein is my Father glorified, that ye bear much fruit; so shall ye be my disciples." What sort of fruit are we bearing?
Our personal "spiritual state" is irrelevant. Using scripture IS the words of the Holy Spirit. They are NOT our words.