When the rice is ripe and has fruits, it has a certain weight and will be bent down. It is a metaphor that when people mature, they will become humble and know how to learn from others. In layman's terms, it means that as people become more knowledgeable, they know how to keep a low profile. Humility makes people progress, and pride makes people fall behind. This is the truth. I hope you will deeply understand the meaning of this sentence and become a person who is diligent in thinking and asking questions.