Plagiarism -- Remembering JFK

JFK is remembered for the following hortatory remark from his 1961 inaugural speech, presumably written by Ted Sorenson.

“And so, my fellow Americans: ask not what your country can do for you - ask what you can do for your country.”
However, Oliver Wendell Holmes, Jr. said the following in an 1884 Memorial Day Address in Keene, N.H.:
“We pause to become conscious of our national life and to rejoice in it, to recall what our country has done for each of us, and to ask ourselves what we can do for our country in return.”
Khalil Gibran published the following saying in his work titled "The New Frontier", published in 1925 and translated into English in 1947 well before President Kennedy's 1961 Inaugural Address.
"Are you a politician asking what your country can do for you or a zealous one asking what you can do for your country? If you are the first, then you are a parasite; if the second, then you are an oasis in a desert."

Were Sorenson and JFK guilty of plagiarism? Plagiarism constitutes any or all of the following:
• stealing and passing off (the ideas or words of another) as one's own
• using another's words or ideas without crediting the source
• presenting as new and original an idea or product derived from an existing source or sources.
In other words, plagiarism is an act of fraud. It involves both stealing someone else's work and lying about it afterward.