This whole dynamic describes God's kingdom at work in our lives. We take the small seed and plant it in our garden. Our garden is a place of careful cultivation. Then that seed grows to be huge in comparison to where it started.
"The apostles said to the Lord, 'Increase our faith!' And the Lord 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.' " - Luke 17:5-6 ESV
Mulberry tree leaves were used to feed silk worms. Maybe we think of the tree suddenly being shaken free of the ground and rising up into the air to fly off into the sea but perhaps when Jesus speaks of the mustard seed faith He is referring to the dynamic He explained a few chapters back when a man plants something small from God but full of multiplication life and reaps a far larger harvest. It is a dynamic that takes time into consideration. Over a course of months the tree would die, become a useless dead object taking up space and men would uproot it and cast it into the nearest dumping ground.
It speaks of an inner life cultivation also doesn't it. We become gardeners planting seeds in our inner life and reaping a harvest. We say this goes here and that goes there. We plant small seeds by faith and give our soul directions. Uproot the silk worm tree that we were using to weave garments and turn a profit. No, this garden will be for mustard greens that have nutrition and produce a large bounty that we can share with others.
"Then the disciples came to Jesus privately and said, 'Why could we not cast it out?' So Jesus said to them, 'Because of your unbelief; for assuredly, I say to you, if you have faith as a mustard seed, you will say to this mountain, "Move from here to there," and it will move; and nothing will be impossible for you. 'However, this kind does not go out except by prayer and fasting.' " - Matthew 17:19-21 NKJV
The cultivation of an inner garden overflows into the outer spiritual world. Demons obeyed Jesus. Jesus was a man with a cultivated mind. His Father's words and life were His meditation all day long. He prayed at night and starved out the weeds so they never took root in His thinking. When He said, 'Go' the demons went.
This is what the kingdom of God is like.
We believe small things filled with life. We plant God's words in our minds and then they grow tall and fragrant. Yes, The multiplying crop will attract the birds (a reference usually referring to fallen angels) but that is a dynamic that comes with the territory.
When we live this way nothing is impossible for us because we are not the ones doing the work. We don't make the small things grow. God's kingdom is just like that. He makes it grow. He kills the silk worm tree. We say the words but He does it. He moves the mountains and changes our inward terrain. It is His power that makes the spirit world obedient.
We are just gardeners looking for a crop and God Is faithful to give an increase.