There are two factors that, taken together, make plagiarism a danger for those in the Christian ministry. First, those engaged in pastoring and teaching generally love to learn and share what they have learned with others. This is obviously a very good thing.
But second, the guidelines for giving proper credit to those we have learned from are not always clear. Hence, there is a danger that the good desire to share and spread truth will sometimes be carried out, unknowingly, through the untruthful means of plagiarism.
The essence of plagiarism is to give the impression that the ideas or words of another person are actually your own. This can be done intentionally (in which case it is outright theft) or unintentionally—but either way it is wrong.
The tenth edition of Merriam Webster's Collegiate Dictionary formally defines the term "plagiarize" from three different angles:
1. "To steal and pass off (the ideas or words of another) as one's own"
2. "To use (a created production) without crediting the source"
3. "To commit literary theft: present as new and original an idea or product derived from an existing source"
In a nutshell, you have committed plagiarism whenever you use another's ideas or words without crediting or acknowledging the source.
We can spell this definition out more concretely. There are basically three ways in which plagiarism can be committed:
1. Quoting someone else word for word but not crediting them as the source.
2. Paraphrasing another's words without acknowledging the author whose words you are restating. In other words, if you do not quote the person verbatim but instead just change a few words and do not give credit, you have committed plagiarism.
3. Using the ideas of another without acknowledging their source. Hence, even if you state another person's ideas entirely in your own words, you still must credit them as the source of the ideas. The only exception is when the idea is well known and has become common knowledge. For example, if I state that "it is 93 million miles to the sun," I do not need to cite a source. It is common knowledge.
The Problem With Plagiarism
The central problem with plagiarism is twofold: (1) it is stealing; and (2) it bears false witness. Obviously, both of these are unacceptable for Bible-believing Christians (see Exodus 20:15; Mark 10:19; Matthew 15:19, etc). Stealing and bearing false witness fail to love your neighbor as yourself (Romans 13:9). The words and ideas of another person are precisely that—their words or ideas.
To fail to acknowledge their source is to give the false impression that they have originated with you. Hence, plagiarism steals from another and gives a false impression to your audience. Both of these factors should be of utmost concern to the Christian, and especially pastors and teachers who should have the utmost respect for the sanctity of truth.
Overcoming Plagiarism in Preaching and Teaching
It is not hard to avoid plagiarism. All that you have to do is acknowledge the source whenever you quote, paraphrase or use the ideas expressed by another. But, of course, life almost always throws us complex situations where it is not clear how to apply a general principle such as this. Hence, it will be helpful to spell out some specific guidelines.
1. General acknowledgements do not suffice. It is not enough, for example, for a pastor simply to say to his congregation, "Once in a while I use the ideas or words of other theologians. I don't tell you every time I do it because I have reminded you from time to time not to think that everything I say originated with me." Instead, each instance of quoting, paraphrasing or using another's ideas must be accompanied by attribution to the source.
2. Detailed bibliographic data is not necessary. It is not necessary to give detailed information as to the page number, publisher of the book, date of publication and so forth when attributing a source in a sermon. It is helpful to do this in papers, but even then the absolutely necessary thing is to name the person from whom you got the idea or quote, and if possible the specific book or lecture or article.
3. Common knowledge does not need to have its source cited. "Common knowledge" does not necessarily mean that everyone in your audience knows the information. What is it then? The Purdue University English Department suggests helpful criteria. You have "common knowledge" when (1) "You find the same information undocumented in at least five other sources"; (2) "You think it is information that your readers will already know"; (3) "You think a person could easily find the information with general reference sources" (source). Hence, "Jonathan Edwards was born in 1703" is common knowledge. "God is most glorified in us when we are most satisfied in him" is not common knowledge.
4. If the original source simply cannot be found, it is acceptable to say "As someone has once said…" (Most sources, however, can be found. For online searches, www.google.com is indispensable. You might also try the new "Search Inside the Book" feature at Amazon.)
5. Restatements, in your own words, of the positions of general movements do not necessarily require citation. For example, it is OK to say, "Calvinism holds X" without detailing the history of the movement or even discussing its historical origins in general. However, a restatement of the Calvinist position that follows the structure or outline or unique wording of someone else's prior work on the Calvinism would require citation.
6. The preaching of another's sermon is usually a bad idea, but is not plagiarism if the original author is clearly cited.
7. To base the structure of your sermon on someone else's sermon, but to use your own words, is plagiarism. The author on whose work you are basing the structure of your sermon would need to be cited.