In Mark 11, Jesus and his hungry disciples were leaving Bethany, headed for Jerusalem. Coming to a fig tree in full leaf, they believed there would be real fruit to eat. The fruit is ripe when the tree is in full leaf. Finding no fruit, Jesus rebuked the tree for possessing the appearance of real fruit, but having none.
This was a picture of what Jesus found at the temple in Jerusalem. Everything had the appearance of real spirituality outside, but there was nothing real inside. Jesus rebuked them for their hypocrisy, and drove them from the temple courts.
The next day as Jesus and His disciples passed the same fig tree. It no longer possessed the appearance of real fruit. Jesus used this example to teach his disciples how real forgiveness, real faith, and real prayer work together to move mighty mountains for real!