A response to the "small group questions" for the 24 March 2019 message at First Pres, Boulder. 
Here is another illustration Jesus used: “The Kingdom of Heaven is like a mustard seed planted in a field. It is the smallest of all seeds, but it becomes the largest of garden plants; it grows into a tree, and birds come and make nests in its branches.”
Jesus also used this illustration: “The Kingdom of Heaven is like the yeast a woman used in making bread. Even though she put only a little yeast in three measures of flour, it permeated every part of the dough.”
Jesus always used stories and illustrations like these when speaking to the crowds. In fact, he never spoke to them without using such parables. This fulfilled what God had spoken through the prophet:
“I will speak to you in parables.
I will explain things hidden since the creation of the world.”
excerpt from the New Living Translation of the gospel of Matthew 
Throughout this series we have been saying that something is happening in God's Kingdom that isn't obvious. What about Jesus' ministry seems small? What about your own current ministry seems small?
I think this might again be one of those points that is already so ingrained in me that I don't know how to look past it. My life is so full of blessing, and I credit it to God; I don't know how to consider it small.
Maybe another way to say this is that I have already seen the mustard seed grow to the plant in the past. Even now, when I see "mustard seeds," I'm already looking forward to what God has promised, often almost discounting the time it will take for the plant to grow. 
How would you describe what is happening to the smallness in these parables?
I particularly notice that the seed and the yeast are types of the "kingdom of heaven" in these parables; not the word, nor the believers. In these illustrations it is revealed, over time, that the effectiveness of the seed or the yeast isn't confined to their initial appearance; they are alive, and their inherent potential allows them to grow beyond a shallow understanding of their bounds.
Do you see a difference in meaning or emphasis between the parable of the mustard seed and the parable of the yeast? What nuance or difference do you notice?
It's a weird thing; but I generally assume that yeast in Jewish imagery is a symbol of sin. Paul even makes this same reference to sin as yeast permeating a whole loaf.  It's probably nothing; but I'm always knocked a little off-balance when a metaphor like this is used toward inconsistent ends. Part of me wants to dismiss it as a simple liteary issue: nothing says that the kingdom of heaven and sin can't both operate like yeast in a loaf of bread. Except, if you're looking at the world as flour or dough, and there's a little of the kingdom of God and a little sin, which permeates the loaf? If it's the sin, then what power is there in the kingdom of God? But if it's the kingdom, then what purpose is there in Paul's caution?
Sometimes details in a parable just add detail, but sometimes they add additional meaning. The birds in verse 32 are one such place. What additional meaning might have been intended if we also read Ezekiel 17:23 or 31:6?
It will become a majestic cedar, sending forth its branches and producing seed. Birds of every sort will nest in it, finding shelter in the shade of its branches.The birds nested in its branches,and in its shade all the wild animals gave birth.All the great nations of the worldlived in its shadow.
I'm also reminded of Matthew 6, where Jesus uses birds as a type of a creature who lives its life in patient, faithful dependence on God.  Our pastor, in his sermon, compared the birds in our passage today to those in the world who might otherwise feel unwelcome but should be welcomed through faith in Christ into the body of believers as children of God. But I read it more that the kingdom of God, as seen in the example of the mustard tree, is an expression of God's providence and care as promised to those who trust in him.
60 pounds of flour is a HUGE amount of flour. Interesting detail, or theologically important?
I don't know, man. The NIV translates "three measures" into "sixty pounds"; but a couple other translations say "fifty pounds"; and still many more just keep the actual language of "three measures" from σάτα τρία. Barnes claims these are "small measures"; but according to Strong's concordance the measure is a translation of a Hebrew measure, סאה. Barnes does then say that the quantity is likely "about a peck and a half", or three dry gallons, which is roughly equivalent to all the other assessments of the measure; and some random unit converter on the Internet claimed to me that three gallons of flour would weigh something like fifteen pounds. So who knows?
With all this uncertainty, I'm loathe to draw any significance from the specific quantity of flour. It seems sufficient to me to understand that there is significantly more flour than yeast, but the yeast affects the whole batch. Perhaps one day Jesus will tell me more specifically what he was trying to convey with his specific measurements.
Verse 35 quotes Psalm 78:2. What might this mean? What are the things in this parable that have been hidden but happening since the creation of the world? 
I think this is one of those parts of life in Christ that are difficult to appreciate retrospectively. We have had the benefit of Christ's teaching for thousands of years now. We might look at our history, our people, and the world, and "long for our bodies to be released from sin and suffering" ; but it's my belief that we don't fully comprehend, even now, the affect that God's grace through Christ has had on our world. More plainly, I think things were much worse in the world before Christ, but we have lost track because we have only ever known the age of grace.
We read Christ's teachings now, and much of it has so permeated our culture--even what we would consider secular culture--that some would consider it common knowledge. But the fact is that before Christ, no-one thought you should "love your enemies! Pray for those who persecute you!" The thing that had been hidden was that "In that way, you will be acting as true children of your Father in heaven."  It is the character of God that we have misunderstood, and that character is revealed in Christ.
|||The Kingdom Underground: Mustard Seeds|
|||1 Corinthians 5:6-8|