Matthew 13:31

Christ takes the grain of mustard seed, by which is to be understood Christianity both as a doctrine and as an organised society, and plants it in His field, which is the world. Mustard seed] The vegetable or herb, not the so-called mustard tree, is meant. In hot countries it sometimes grows to a great size. The Jerusalem Talmud says, 'There was a stalk of mustard in Sichin from which sprang out three boughs, of which one was broken off, and covered the tent of a potter, and produced three cabs (12 pints) of mustard.' Rabbi Simeon said, 'A stalk of mustard was in my field, into which I was wont to climb as men are wont to climb into a fig-tree.' Although the mustard seed is not really the smallest of all seeds, it was so in popular estimation. The rabbis called the smallest possible quantity 'the quantity of a grain of mustard,' and Mahomet uses the same expression in the Koran.