Quote attributed to Mandela

In her book, Ms Marianne Williamson writes:

Our deepest fear is not that we are inadequate. Our deepest fear is that we are powerful beyond measure. It is our light, not our darkness that most frightens us. We ask ourselves, Who am I to be brilliant, gorgeous, talented, fabulous? Actually, who are you not to be? You are a child of God.

‘A return to love: Reflections on the principles of a course in miracles’ by Ms Marianne Williamson