The shorter the text of a parable, the closer it is to the very words that came out of Jesus' mouth: it has not been altered or enlarged by catechetical adaptations. Here we have two short parables: let us come close to them, as though listening to Jesus' preaching, ignoring the city background of Luke, who places the mustard tree in a garden: mustard is a wild tree; he never saw one!

What do these two parables have in common? The kingdom begins small and hidden, suddenly breaks forth with life, and is not confined to any single group. The symbol of the branching off and the birds of the air, used in various contexts in the Old Testament (Cf Dn. 4:11; Ez 17:23; 31:6), points to the universal aspect of the kingdom. And the transforming action of the leaven is "no-stop", till the whole mixture is leavened out. Such is the kingdom of God, which we are called to promote: Our objective is the whole world. The Holy Spirit has availed us of a continuous thirst for action, and an energy that transforms everything (we are leaven). But, unlike the leaven, we never say: "mission accomplished"; like the mustard tree, we will always find space for further and further ramification.