"Grant often quoted the following statement, which is sometimes attributed to Ralph Waldo Emerson: “That which we persist in doing becomes easier for us to do—not that the nature of the thing is changed, but that our power to do is increased.”

and in a talk by President Thomas S. Monson talking about Heber J. Grant.

"A favorite quotation of his is attributed to Ralph Waldo Emerson: “That which we persist in doing becomes easier to do; not that the nature of the thing has changed, but that our capacity to do has increased.”

IDK maybe Grant said it so much when he was alive that people thought it came from him?