So Jesus answered and said to them, “Have faith in God. For assuredly, I say to you, whoever says to this mountain, ‘Be removed and be cast into the sea,’ and does not doubt in his heart, but believes that those things he says will be done, he will have whatever he says. Therefore I say to you, whatever things you ask when you pray, believe that you receive them, and you will have them. Mark 11:23-24
Jesus is the one who originally said this not any preacher or evangelist you’ve ever heard. It was true then and it’s true now.