Just as a plant grows little by little, so a person who hears and accepts the Kingdom message grows spiritually little by little (See paragraph 5)

5. How did Jesus illustrate gradual growth?

5 Jesus used an illustration to explain how the Kingdom message we preach is like a tiny seed that gradually develops in honesthearted ones. He said: “The seeds sprout and grow tall—just how, he [the sower] does not know. On its own the ground bears fruit gradually, first the stalk, then the head, finally the full grain in the head.” (Mark 4:27, 28) What point was Jesus making? He was explaining that just as a plant grows little by little, so a person who accepts the Kingdom message grows spiritually little by little. For example, as our sincere Bible students draw closer to Jehovah, we begin to see the many fine changes that they have made. (Eph. 4:22-24) But we must remember that it is Jehovah who makes that tiny seed grow.—1 Cor. 3:7.