Matthew 17:20
And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.
Jesus spent three years trying to grow the faith of His disciples because He knew they needed a great faith if they were to turn the world upside down with the Gospel of Jesus Christ. Their faith at times seemed anemic, but we do see their faith grew. In one instance, Jesus mentioned to them that if they had the faith as a grain of mustard seed that they would be able to tell a mountain to be removed, and it would be removed. In this statement, Jesus taught several lessons on how to grow your faith.
First, it does not take much faith to do great works. God is very willing to do great works through you, but you must act on faith to see those great works done. God knew we would struggle with faith, and that is why He is willing to work with a little faith to do great things. It is not that God won’t do great works; it is that we won't attempt great works for God to honor our faith. You have to attempt something that requires faith for God to do great works through your life.
Second, you must act on the faith you have. It is interesting that God said mountains could be removed if we had faith as a grain of mustard seed. A mustard seed is very small, but God will start with your small faith and grow it if you will just act on the faith you have. God is not concerned with you having faith like other people; He is concerned with you acting on your faith. To say you don't have enough faith to do great works for God is not true. God has given you enough faith to do great works through you. Inside of you is the ability to do great works IF you will act on the faith you have to attempt those great works. God is willing to honor anyone’s faith if they will act upon it, and that includes you.
Third, faith will only grow once you act on the faith you have. You can look at the faith of a Dallas Billington who, by faith built a great church in Akron, Ohio, and say you don't have his faith, but you don't have to have his faith now, but you can have his faith if you will act on your faith. God expects your faith to grow, but there is no need to grow your faith if you don't act on the faith you have. You will learn as you start acting on the faith you do have that your faith will continue to grow because God rewards whatever amount of faith you act upon, which builds your faith.
Fourth, faith will grow exceedingly once you fast and pray. There is a point in the growth of your faith when you must fast and pray to grow it. The disciples could not understand why they could not cast out a devil, and Jesus told them that the reason they could not do it was because this kind goeth not out but by prayer and fasting. When your faith begins to grow, there comes a point when it will require fasting and prayer to make the impossible become a reality.
Do you desire God to do the impossible through you? He cannot do the impossible through you until you act on the faith you have, even if that faith is as a grain of mustard seed. Let me challenge you not to look at another’s faith and say you don't have their faith because God doesn't need you to have their faith to do the impossible through you; all He needs is for you to act on your faith to perform the miraculous through you.