In Matthew 13 there is a collection of parables that explain the nature of God’s Kingdom. They fall into three pairs: two about the growth of the Kingdom (the mustard seed, and the yeast), two about the value of the Kingdom (the treasure, and the “pearl of great price”), framed by two about the make-up of the Kingdom (the wheat and the tares, and the fishing net).
Firstly, the Kingdom’s progress. (Matthew 13:31-33) No sudden, cataclysmic divine intervention is to be expected – not in the short-to-medium term, at any rate. How long does it take an acorn to grow into an oak tree? Centuries! And if you sit down and watch a seed for any length of time, you won’t actually see anything happening; the speed of development is too slow to register on our human perceptions. Only when we look back over two millennia can we really see how enormously the Kingdom has grown in that time. As with a growing seed, so with yeast: the rising of the dough is a slow and silent process, and only over a period of time can we appreciate what a difference the yeast has made. The picture of the yeast adds a little more: the yeast can spread through and transform the dough only if it is thoroughly mixed with it. So we cannot expect to see God’s Kingdom being extended through the world unless we are making contact with the world.
Secondly, the Kingdom’s value. (Matthew 13:44-46) Some people stumble across it by accident; others find it only after a long and frustrating search. But however we come to recognise it, we realise that it is the most important thing in our whole lives – something for which no sacrifice is too great to make. The subjects of the Kingdom are totally committed to it, and have no regrets. “Whatever was (previously) to my profit I now consider loss for the sake of Christ.” (Philippians 3:7)
Thirdly, the Kingdom’s composition. (Matthew 13:24-30, 47-50) The world is like a field where many different plants are growing, or like a sea full of many different kinds of fish. There are, basically, only two kinds of people – the “wicked” (the children of the devil) and the “righteous” (the children of the Kingdom) – but it is not necessarily obvious to us which are which! (“Tares”, so I understand, are a particular kind of weed that looks identical to wheat in the early stages of growth) Not all who appear to be members of the church are actually members of the Kingdom; conversely, there will be some members of the Kingdom who have never been formally attached to any church. God’s judgement will not take place until the end of the age, and only then will there be a clear separation between those who are “in” the Kingdom and those who are “outside”. In the meantime, “judge nothing before the appointed time; wait until the Lord comes. He will bring to light what is hidden in darkness and will expose the motives of men’s hearts.” (I Corinthians 4:5)