I wrote earlier of how the fig tree and mountain of Mark 11 were spoken and written to indicate God’s judgment upon faithless Israel, and to encourage the early church to persevere in prayer for deliverance from persecution. Quoting Mark Horne:
Jesus is discussing the prayers which the early Church will have to pray in the face of opposition from the Temple Mount. . . . Jesus is not speaking of mountains in general. He has made a point of saying which mountain will be cast into the sea by believing prayer. . . . Just as Jesus cursed the fig tree, so will God deliver the Church through the prayers of the saints.
Understanding this gives us insight into the timeframe Jesus was implying when he said that “it will be done for” the one who has such faith. The persecution of Saul began as early as the year of Jesus’s death and ascension, AD 30. There was a “near” deliverance for the church in the conversion of Saul. Fourteen years later, James the brother of John was killed by Herod Agrippa, and there was another “near” deliverance in the death of Agrippa in AD 44. Then the church continued to struggle with persecution. The final removal of this mountain did not come until AD 70 when Rome destroyed Jerusalem.
Counting backwards, the church’s prayers for deliverance continued for 26 years from the death of James, and 40 years from the death of Stephen. When the church prays, we are to have this manner of persistent and patient faith. Not every fig tree withers overnight.
See also: Patience.