Mat 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
A Mustard Seed of Faith can move Mountains, physically and spiritually. A Mountain of Sin, a Mountain of Fear, and a Mountain of Worry. Jesus knows our weakness and that the flesh is weak, but the spirit is willing. Jesus already did the hard part.
The Mustard Seed does not do any good setting in a jar. We need to plant it and watch it grow.