What does "remove assignment" prompt mean in my lambda expression?

I have a R# prompt saying that I should "remove assignment" graying "message =".

public static void ThrowIfNullOrEmpty(string[] names, string[] values, string commonMessage)

       {

           var messages = new string[names.Length];

           // initialize all elements of array with the common string message;

           Array.ForEach(messages, message => message = commonMessage);

           ThrowIfNullOrEmpty(names, values, messages);

       }