Sakyamuni had numerous followers and believers. Because their social and educational backgrounds were so diverse, he expounded the law in various ways according to each individual’s background. Furthermore, as the level of their understanding also differed, the Buddha adjusted his ways of preaching accordingly. This approach is called the expedient method of teaching. It resulted in a variety of sutras. The teachings in these sutras were not necessarily the same. They were presented as expedients for one single purpose: to lead people to aspire to the same enlightenment as that of the Buddha. Because all of these expedients came out of the Buddha’s wisdom and compassion, and were results of his desire to communicate the truth of his enlightenment, their fundamental idea must be one and the same despite their apparent differences.