A parable is an extended metaphor or simile frequently becoming a brief narrative, generally used in biblical times for didactic purposes. We are in the Gospel of Matthew and continue reading Jesus’ parables. Today is the parable of the mustard seed. In these verses, the man is Jesus Christ and the field, the world. The grain of mustard seed is the preaching of the Gospel and the Church, which will spread throughout the world from very small beginnings. The parable refers to the universal scope and spread of the Kingdom of God: The Church, which embraces all humanity of every kind and condition, in every latitude and all ages, is forever developing despite obstacles, thanks to God’s promise and aid. The comparison of leaven is taken from everyday experience. Just as leaven gradually ferments all the dough, the Church spreads to convert all nations. The leaven is also a symbol of the individual Christian. Living in the middle of the world and retaining his Christian quality, he wins souls for Christ by his word and example: Our calling to be children of God amid the world requires us not only to seek our own personal holiness but also to go out onto all the ways of the earth, to convert them into roadways that will carry souls over all obstacles and lead them to the Lord. As we participate in all temporal activities as ordinary citizens, we are to become leaven acting on the mass.