The kingdom of heaven is like to a grain of mustard seed. — The two parables that follow are left without an explanation, as though to train the disciples in the art of interpreting for themselves. And, so far as we can judge, they seem to have been equal to the task. They ask for the meaning of the Tares, but we read of no question about these.
It is scarcely necessary to discuss at any length the botany of the parable. What we call mustard (Sinapis nigra) does not grow in the East, any more than with us, into anything that can be called a tree. Probably, however, the name was used widely for any plant that had the pungent flavour of mustard, and botanists have suggested the Salvadora persica as answering to the description. (See Bible Educator, I. 119.)
The interpretation of the parable lies almost on the surface. Here again the sower is the Son of Man; but the seed in this case is not so much the “word,” as the Christian society, the Church, which forms, so to speak, the firstfruits of the word. As it then was, even as it was on the day of Pentecost, it was smaller than any sect or party in Palestine or Greece or Italy. It was sown in God’s field of the world, but it was to grow till it became greater than any sect or school, a tree among the trees of the forest, a kingdom among other kingdoms (comp. the imagery of Ezekiel 31:3; Daniel 4:10), a great organised society; and the “birds of the air” (no longer, as before, the emblems of evil) — i.e., the systems of thought, institutions, and the like, of other races — were to find refuge under its protection. History has witnessed many fulfilments of the prophecy implied in the parable, and those who believe that the life of Christendom is an abiding life will look for yet more.