The Parable of the Mustard Seed
30 Again he said, “What shall we say the kingdom of God is like, or what parable shall we use to describe it? 31It is like a mustard seed, which is the smallest seed you plant in the ground. 32Yet when planted, it grows and becomes the largest of all garden plants, with such big branches that the birds of the air can perch in its shade.”
33 With many similar parables Jesus spoke the word to them, as much as they could understand. 34He did not say anything to them without using a parable. But when he was alone with his own disciples, he explained everything.
Mark 4:30-34 (NIV)