While I sit drinking my Wittenberg Beer with Philip and Amsdorf, the Gospel runs its course and overthrows empires. -- Martin Luther

Karl Barth connects this Martin Luther quote to the Gospel lesson for tomorrow, Mark 4:26ff Unlike Jesus Kingdom parables about building houses, this parable makes clear that the Kingdom of God will come whether we work at it or not. Building buildings needs stone masons, carpenters, joiners, roofers and on and on. The growth of the Kingdom of God as progress from seed to plant will happen whether one "sets hands to work or folds them or even lays them in [our] lap [we] can only be a spectator and affirm that it takes place "He knoweth not how" (Mark 4:28)--in a process which continues both when he works and also when he does not, but is perhaps, in the words of Luther, while, "Drinking beer with Philip and Amsdorf" (Philip Melanchthon and Nicolaus von Amsdorf)
Barth goes on (Book IV, vol 2 pp632 ff) to contrast these two parables of building and sowing

It is a matter of their [Christians] spiritual growth, and not therefore of a growth which they themselves can direct. It will continually have for them the greatest of surprises, sometimes glad and sometime bitter. In moments when [the church] is resolved to offer "reasonable service," the plans and efforts of Christians will have to be ruled by it, and not the reverse. To their own astonishment it will continually exalt the lowly, enrich the poor, give joy to the sad and make heroes of the feeble.... And as it grows spiritually, there is no compulsion but it may grow in the first way, extensively and numerically. (p. 650.)

 What are the marks of such growth? Barth lists them nicely:

• growth in faith (2Cor 10:15)
• increase in love (2 Thess 1:3)
• increase in the knowledge of God (Col 1:10ff) with strengthening endurance and joyful patience.
• growth in the fruits of righteousness (2Cor 9:10)
• growth in grace (2 Pet 3:18)
• Incrase of comfort (2 Cor 1:5)
• Thanksgiving (2 Cor 4:15)
• the grace for every good work (2 Cor 9:8)
• Hope (Rom 15:13)
• enrichment of love in knowledge and understanding (Phil 1:9)

And then he summarizes by saying that the increase of growth for the Christian Community is "both horizontal and vertical" and is the spiritual progress of the sancti in their relationship to the sancta.