You know there are a lot af catchy ways to say reuse someone elses ideas or work
FBC Pastors wife said "using another man's stick to beat the Devil"
shannonL kind of used one I had heard "milking another man's cow to make your butter"
blackbird quoted Adrian Rogers, "If my bullets fit in your gun---load and shoot!"
The pastor I was called to preach under told me to
Take another man's bones, but hang your meat on them.
That was always my favorite. How many others can we think of?
Most preachers I have known would be flattered to know that some part of one of their sermons was useful to another preacher. Reading sermons of great preachers of the past that relate to the text I am working from is a part of my normal preparation and study. Another preacher I served under once told me to "read at least one sermon from someone else every day."
If you have been listening to preaching for very long at all some ideas are bound to recirculate. I went to a preachers meeting one time and we heard a great message. I wrote down the outline knowing that I would work it into a future message. After the service I was talking with another preacher about the message and his wife showed me where she had written the outline down in her bible, over 30 years before - the exact same outline.
I preached a revial meeting one time and after the service a visiting pastor told me he knew where my outline came from. He said that it was from the "outline file" at fruitland (Fruitland Bible Institute in Hendersonville NC. I have never actually been there but a lot of their graduates pastor churches in Western North Carolina). I thought it was a completely original message, but he said my outline had been on file at Fruitland for 20 years.
Well, not to ramble but my feeling is preach what God lays on your heart. He should be the ultimate author anyway. If you feel you were overly influenced by another man's work, give him the credit.