Matt 21:18 (NASB) Now in the morning, when He returned to the city, He became hungry. 19 And seeing a lone fig tree by the road, He came to it, and found nothing on it except leaves only; and He ^said to it, "No longer shall there ever be [any] fruit from you." And at once the fig tree withered. 20 And seeing [this,] the disciples marveled, saying, "How did the fig tree wither at once?" 21 And Jesus answered and said to them, "Truly I say to you, if you have faith, and do not doubt, you shall not only do what was done to the fig tree, but even if you say to this mountain, 'Be taken up and cast into the sea,' it shall happen. 22 "And all things you ask in prayer, believing, you shall receive."

Mark 11:23 (NASB) "Truly I say to you, whoever says to this mountain, 'Be taken up and cast into the sea,' and does not doubt in his heart, but believes that what he says is going to happen, it shall be [granted] him. 24 "Therefore I say to you, all things for which you pray and ask, believe that you have received them, and they shall be [granted] you.