First, He continually assures us that He is ready to use His power through us if we only have sufficient faith.  Jesus here says if the disciples have only a grain of faith, they could uproot and transplant trees, or in Matthew 17:20 they would move mountains.  He of course, is using figurative language, to be sure, but He means that with enough faith they can do things that seem as impossible as moving mountains.  Yet, if a mountain must be moved, as in digging the Panama Canal, men with enough faith can do it.  Repeatedly Jesus assures His disciples of the readiness of His Father to use His power through them.  In John 14:13, He says, "Whatsoever ye shall ask in My name, that I will do." In John 15:7 He urges, "If ye abide in Me, and My words abide in you, ask whatsoever ye will, and it shall be done unto you." Yet in John 16:2 He says, "Hitherto ye have asked nothing in My name; ask and ye shall receive." He seems almost disappointed that they have asked nothing.  Evidently, they had been so contented in His presence, seeing His miracles, hearing Him teach, that they had felt no need of anything more.  But Jesus knows the dark hours to come, and He wanted to open their eyes so that when the darkness came they would instantly know the source of power and be assured of His readiness to help.

In the second place, in addition to assurance, Jesus continually demonstrates His power to help.  His disciples see Him open the eyes of the blind, heal the sick, cleanse the lepers, and even raise the dead.  When He gets the message that Lazarus is sick, instead of going immediately to heal him, He waits three days until the body would be decaying.  He explains to His disciples, "I am glad for your sakes that I was not there, to the intent that ye may believe." To strengthen their faith, He performs what would seem an impossible miracle.  Finally, again and again He foretells His own death and resurrection.  It was simply beyond their belief; it could never happen to Him.  Then when they saw Him on the cross, their faith and hope died.  But then, on the third day, He appeared to the sorrowing group in the upper room, they finally had a faith that could never again be shaken.  Looking back years later, Peter says that He "begat us again unto a living hope through the resurrection...from the dead." It was like being born again.

In the third place, Jesus not only emphasizes the power of faith and demonstrates that power but finally He suggests the secret of how faith can grow as God uses his power through us. "If ye have faith as a grain of mustard seed." Though the smallest of all seeds, when planted and allowed to grow, the mustard seed becomes a great plant.  So a grain of faith set to work may at first move only a pebble, but if cultivated, God through it, can ultimately do what might seem as impossible as moving a mountain.  By such growth God tries to develop the faith of men.  When He told Abraham that, if He would leave His people and go into a land that He would show him, He would bless the world through his seed, Abraham went immediately.  The first step was easy, for land was free and grass was abundant up the Euphrates River.  But when he went down to Egypt, his faith failed, and he allowed his wife to be taken by pharaoh because, as he explained later to Abimelech, he thought there was no fear of God in that land.  But when God restored Sarah to him, his faith was strengthened.  Yet years passed, and he had to remind God that the child had not come.  God renewed His promise, but again years passed and no son.

Then at Sarah's suggestion, they tried to help God out of His dilemma by using Hagar.  But God said the son must come through Sarah, and again the years passed.  Finally, when Sarah was ninety years old, Isaac was born, and Abraham saw that God could fulfill His promise against all the laws of nature.  So when God told him to offer Isaac as a sacrifice, His faith did not fail, for as the writer in Hebrews 11:17-19 says, he now believed that God would raise Isaac from the dead to fulfill His promise.  Thus, over the years God had developed a man who would become a model of faith for all later generations.

When J. M. McCalem went to Japan and the Merrits and Shorts went to Africa, no church had faith enough to guarantee their financial support.  They went on faith.  But as churches saw how their faith worked, they discovered that they could support a missionary themselves, and today our mission program around the world has a support that would have seemed impossible to the churches a generation ago.  In 1891, when Harding and Lipscomb started our first Christian college, no group of Christians would have had faith enough to guarantee its financial support.  Like Abraham, they started out on faith.  Gradually, as this school multiplied, the faith of Christians grew, until the great system of schools today, blessing the lives of thousands of young people, would seem to these two founders an impossible miracle.  So the Lord says, plant your grain of faith today, and the Lord can make it grow till it can figuratively move the mountains.  This is the secret of how faith grows.  "Try Me," said the Lord through Malachi, "and see."