Author and pastor Doug Wilson has a lengthy post big-named Christians, ghostwriting, and plagiarism. He’s had to deal with plagiarism accusations in the past and he describes some of them:
One of my first books was one called Persuasions. In that book I have a character compare monogamy to buying a musical instrument and learning to play it, which is not like buying a record album and being stuck with listening to just one album over and over again. Years later I had a friend tell me he was disappointed that I had used C.S. Lewis’s analogy when he thought I was fully capable of coming up with my own. But I had no idea I was borrowing from Lewis. I am sure I got it from Lewis, and had used it in many witnessing conversations, and then when I wrote a book of witnessing encounters, in it went.
Other times I use something consciously. I conclude my weekly homily at the Lord’s Table with a phrase I got from John Bunyan — “come, and welcome, to Jesus Christ.” Should I feel bad about not saying, every week, “as Bunyan once said . . .”? But I don’t feel bad.
This reminds me of some devotional emails I used to write. One man praised my writing highly twice, both times after I had simply forwarded a portion of a Puritan prayer printed in The Valley of Vision. I thanked him, but wondered if he thought what I had just sent out was mine. I’m still not sure.