“All by itself the soil produces corn – first the stalk, then the ear, then the full kernel in the ear. As soon as the grain is ripe, he puts the sickle to it, because the harvest has come”. 
Mk 4:28, 29 NIV 

Farming is about harvesting. A good harvest supplies food to those who buy it. It also makes the farmer happy because the size of the harvest determines his income – until the next crop is due. 
Today harvesting is done by combine harvesters, big machines that cut the corn, thresh out the grain from the stalks and husks, and then bale the straw in big bundles, collecting the grain in sacks. In Christ’s day the corn was cut by a hand tool, the sickle which was a kind of curved knife. Jesus was saying to his disciples that they don’t grow the faith of people. God himself does that by the work of the Holy Spirit and he works in hidden, silent ways. But then there is a time when the farmer has to judge that the crop is ready and he has to work hard to harvest it. So the spiritual worker, when God has brought people to maturity of faith, has to bring to a climax their commitment to God and “harvest” them for the church. Soon the disciples of Jesus would be going out and reaping the spiritual harvest of those who were ready to become disciples themselves. 
Jesus always points us forward to what he is about to do. There is preparation. There is all the silent and hidden power at work. Then he brings it to fruition and fulfillment in the flowering of faith and the growth of servant ministry by those in whom his work matures. 

Lord, point me forward to your future working.