The prophet Zechariah had pictured the catastrophe of the future judgment day by saying that the Mount of Olives would split in half, effectively turning the land of Israel into a level plain (Zec 14:3–5,10). Jesus picks up this imagery and makes it even more dramatic. With this promise of God through Zechariah in mind, Jesus says while standing on the Mount of Olives, “If anyone says to this mountain, ‘Go, throw yourself into the sea,’ . . . it will be done for them” (Mark 11:23, emphasis added). Saying this is a call for the judgment day to come.

Because God is faithful to his promises, it will indeed come. In fact, Jesus knows that the disciples are already praying for the coming kingdom of God, which will be ushered in by the judgment day. He therefore calls on them to recognize that the things they are praying for and asking for are no longer things of the distant future; he tells them, “Believe that you have received it, and it will be yours” (Mark 11:24).

Jesus has brought the kingdom of God near, and the only thing that must happen before the resurrection day arrives is Jesus’ imminent death.

The last days’ harvest is about to occur, and the fig tree shows that Israel is not ready. But what about the disciples? They need to believe their prayers are being answered right now. And if the judgment day is about to arrive, then so is the forgiveness that God promised and that Israel longed for (Isa 40:3). If so, then on the eve of its arrival, it is time for the disciples to forgive others as well (Mark 11:25).

Taken from the NIV Grace & Truth Study Bible.