Acts 19:13-15 — Then certain of the vagabond Jews, exorcists, took upon them to call over them which had evil spirits the name of the Lord Jesus, saying, We adjure you by Jesus whom Paul preacheth. And there were seven sons of one Sceva, a Jew, and chief of the priests, which did so. And the evil spirit answered and said, Jesus I know, and Paul I know; but who are ye?

So what’s the big deal about witnessing and missions? I say it’s about changing relationships from “who you know of” to “who you know“. Myra focused my attention on this crucial difference as she drove me to work on Thursday.
When I talk about knowing somebody, I’m really talking about intimate personal knowledge.
The sons of Sceva are a perfect illustration of what I mean. They plainly “knew of” Jesus, but they didn’t “know” Him. In fact perhaps it was worse, since they were plainly claiming to speak with His authority and they were frauds … And the evil spirit knew it!
The sort of knowledge I’m talking about is the kind of knowledge Jesus was talking about when He said “I am the good shepherd, and know my sheep, and am known of mine. As the Father knoweth me, even so know I the Father: and I lay down my life for the sheep.” (John 10:14-15). The word He uses is “ginosko”. The Complete Word Study New Testament, by Greek scholar Spiro Zodhiates, defines “ginosko” as “to know experientially.” It’s about a very personal, and much more than just a general, knowledge.
We believe that everybody knows of God. The Apostle Paul said:

For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness; because that which may be known of God is manifest in them; for God hath showed it unto them. (Romans 1:18-19)

If everyone has the knowledge of God, our job is to reach out and be the channel through which they gain the crucial intimate personal knowledge that is the result of getting saved and then getting remade in the likeness of His Son. When I thought about that I realized that when I tried to witness (side note, if you are “trying” to witness, you’re almost certainly doing it wrong) I was focusing entirely to much on what I knew, and Who I knew of — and not nearly enough on who I am and who I know. How about you? Like me, do you need to change your approach?