In Matthew's presentation of these three parables about the kingdom of heaven, the disciples interestingly enough only ask for an explanation of the first and lengthier one. We may guess that they found the other two parables easier to understand, possibly because both are very positive and encouraging, dealing as they do with growth and transformation.

The first parable needs explanation, precisely because it is not all positive: there are weeds among the wheat. Even the master's attitude seems strange to us who, perhaps, too easily look for facile solutions. We are puzzled, even frightened, by the presence of evil in the world, and would be happy to have it rooted out immediately. But God, it seems, is patient even with evil!

Yet Jesus suggests that both the weeds and the wheat represent human beings, "all those who do evil" and "the virtuous". Perhaps we are to understand that God's patience is not with evil as such, but with us human beings - we are all too capable of evil, but we can repent and reform.