Oprah was once asked on live TV what she knew for sure. Now, 16 years later she has an answer and she's revealing it to ET.
"What I know for sure is no matter what you're going through, this too shall pass," said Oprah. "And that all trials stands to have you look at yourself and say, 'Who am I really?'"
Oprah came to this realization through the help of her late friend Dr. Maya Angelou.
"I remember calling Maya Angelou one day crying," said Oprah. "She said to say thank you right now. I was like, 'Say thank you? Why say thank you when you're going through the worst of times?' You say thank you because you know your faith is strong enough. Your belief is strong enough. You will get to the other side. This too shall pass."
Maya Angelou also once told Oprah that her biggest gift was answering the call. Oprah seemed to agree.
"My biggest mistakes have always come when I didn't listen to that little voice," said Oprah. "The thing that we do have -- that everybody has -- is that voice that guides. I call it my spiritual, personal GPS, and I've made my biggest mistakes when I didn't listen to that."
Oprah left us with a positive message for those out there who are currently going through trials.
"It doesn't matter what you're going through right now or what you've been through," said Oprah. "There is not one single thing that has ever happened to you that is going to be wasted. Everything that has happened to you has really happened for you to build strength."
Watch the video to hear what Oprah has to say about the power of gratitude.