There's a vast difference between faith "like" a mustard seed and faith "the size of" a mustard seed.
Jesus said, “If you had faith like a grain of mustard seed, you could say to this mulberry tree, ‘Be uprooted and planted in the sea,’ and it would obey you" (ESV, Luke 17:6).
The NIV says, "Faith as small as a mustard seed"--which can be confusing since Jesus was not at all referring to the physical size of the mustard seed.
Faith "the physical size of" the mustard seed would be a very small faith, for sure.
But faith "like" the mustard seed is quite remarkable. It believes and trusts that, despite its tiny size and complete dependance on the goodwill of the gardener, it is destined to become a great plant.
A mustard seed trusts that, despite his own tiny size, the Almighty will nevertheless not leave a single one of His promises unfulfilled. Rather, He will work out everything in conformity with the purpose of His will (Ephesians 1:11). And He will watch over His Word to perform it (Jeremiah 1:12).
That is something altogether different than "having faith in ourselves" that, by tapping into some mysterious pool of inner strength, we can will into existence the thing we want. Or, like King Saul, take matters into our own hands.
A mustard seed puts his faith in the Gardener, not himself.
Of course, it's nice to have faith in yourself. But it's not really necessary.
Instead, let's anchor our faith in the trustworthiness of the Gardener and the promises of His Word.
Until every church disciples every man…