22 And ofttimes it hath cast him into the fire, and into the waters, to destroy him: but if thou canst do any thing, have compassion on us, and help us. 23 Jesus said unto him, If thou canst believe, all things are possible to him that believeth. 24 And straightway the father of the child cried out, and said with tears, Lord, I believe; help thou mine unbelief. Mark 9:22-24
The man with the lunatic son came to Jesus for help, after he had gone to the disciples. The disciples could not heal the son but the father knew where he could get help, straight to the source – Jesus.
Jesus then said to the father, as well as to the disciples, “If thou canst believe, all things are possible to him that believeth.” We need to believe; Jesus can do and will do if we believe. It is a two part equation (believe = all things are possible). How much faith (belief) do we need?
Jesus said, "If ye had faith as a grain of mustard seed, ye might say unto this sycamine tree, Be thou plucked up by the root, and be thou planted in the sea; and it should obey you.” (Luke 17:6)
Mustard seeds are small but the black mustard seed from Israel can grow as tall as twelve feet.
Jesus is saying if we have just a little faith it will grow if we believe and trust His word.
Your faith may be “small” and you might have a hard time believing, then cry out with the father “Lord, I believe, help my unbelief.”