Who said deep in my heart I do believe that we shall overcome one day?

It's an old protest song - https://en.wikipedia.org/wiki/We_Shall_Overcome

We shall overcome
We shall overcome someday
Oh deep in my heart, I do believe
We shall overcome someday

We’ll walk hand in hand
We’ll walk hand in hand someday
Oh deep in my heart, I do believe
We shall overcome someday

We shall live in peace
We shall live in peace someday
Oh deep in my heart, I do believe
We shall overcome someday

We are not afraid
We are not afraid today
Oh deep in my heart, I do believe
We shall overcome someday

The whole wide world around
The whole wide world around someday
Oh deep in my heart, I do believe
We shall overcome someday

– “We Shall Overcome”