When/how did preaching become "witnessing"?

This is an etymology question, not a debate. When/how did “witness” come to its current use in terms of preaching or attempting religious conversion?

The terms are not necessarily synonymous.

Preaching is more akin to teaching, but about religious rather than secular matters.

Someone who tries to convert others to their religion is being evangelical.

Witnessing is just that, stating your experience in front of others. If you have some kind of epiphany, it may be powerful enough to compel you to share it (or try to) with others.

Witnessing MAY be for purposes of conversion, but not necessarily.

Thanks for the clarification. Do you know when the term first came about?

Acts 1:8 (New International Version. Thompson, ed. ©1975). Jesus says,

My WAG is that the early Christians doing their preaching were being Jesus’ “witnesses,” so modern-day Christian proselytizing is called “witnessing.” Maybe the word just has more punch when used that way.

I’d say it’s pretty old. The word martyr comes directly from the Greek words meaning to give testimony as a witness.

Interesting. I grew up going to church every Sunday, but I don’t remember hearing anyone use the word that way until later in life.

Thanks for the info, guys!

Well, I suspect that the current fashion of that use probably has more to do with the increasing presence of Fundamentalist Christianity in mainstream America–and perhaps even more to do with the rise of the Pentecostal movement that parallels it.

I have seen references to “giving witness” at many places throughout history, but I think you are right that it has steadily increased in popular (American) discourse in the last thirty years. My 1986 revision of the OED provides examples ranging from the 1300s to 1833, but I suspect that a later publication would be able to provide several more recent examples.

It appears to me that not a single example given in the OED actually fits into the precise sense and form of “witness” that’s being discussed here. Yes, there are lots of examples where someone is said to “witness to their faith” or to “give witness to their faith” or some such, but none of them use the verb “witness” with no direct object or preposition phrase following it in that sense. I’m speaking here of sentences like “Joe was out witnessing on the street that day.” On the other hand, I think that one of the definitions of “witness” in The American Heritage Dictionary of the English Language does fit this sentence. I think then that “witness” in this precise form and sense is fairly new, but it derives in pretty obvious ways from earlier uses of the word.