Over two thousand five hundred years ago, the Buddha considered each person to have many potential abilities. The development of these potentials, besides depending on the factors of personal effort and self education, also depend on environmental aids, such as good teachers, books, friends known in the Sutras as Good and Wise Advisors, and other learning facilities. The Buddha compared the students to sprouts and the teacher to a gardener. Each sprout can grow by itself into a certain form; it may be beautiful or ugly, and it may thrive or wither. If an experienced gardener takes care of them, often watering and fertilizing them, then they will grow stronger and more beautiful. In other words, watering and fertilizing are the means used in the growing process. Similarly, when teachers transmit the highest knowledge to their students, this does not interfere with the development of their inner potentials. In fact, these two usually complement each other and can hardly be separated from one another.
In the Chapter on the Analogy of Herbs in the Wonderful Dharma Lotus Flower Sutra, the Buddha uses the analogies of small, medium and supreme herbs to describe students of different potentials, dispositions and interests. The small herbs refer to the students of inferior wisdom, the medium herbs refer to ordinary students, and the supreme herbs refer to exceptionally talented students. The Buddha compared himself to a cloud, and the principles he expounded to raindrops. Because each student had different talents and interests, the Buddha used various teaching methods to inspire them to develop their highest potentials.
Even when the Buddha was speaking casually about some principles, each disciple would have different reflections based on his own endowments. This is just like when it rains, all the plants receive moisture, each one absorbing and storing the amount of moisture it needs. That's why the Buddha is said to be a great teacher.