This means spiritual war

Mat 21:18Now in the morning, as He returned to the city, He was hungry. Mat 21:19And seeing a fig tree by the road, He came to it and found nothing on it but leaves, and said to it, “Let no fruit grow on you ever again.” Immediately the fig tree withered away. Mat 21:20And when the disciples saw it, they marveled, saying, “How did the fig tree wither away so soon?” Mat 21:21So Jesus answered and said to them, “Assuredly, I say to you, if you have faith and do not doubt, you will not only do what was done to the fig tree, but also if you say to this mountain, ‘Be removed and be cast into the sea,’ it will be done. Mat 21:22“And whatever things you ask in prayer, believing, you will receive.”Thewayknoxville.com