Hebrews 11:32-33 and Mark 11:23-24
And what more shall I say? For the time would fail me to tell of Gideon and Barak and Samson and Jephthah, also of David and Samuel and the prophets: who through faith subdued kingdoms, worked righteousness, obtained promises, stopped the mouths of lions. 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.