Diamond Sutra: chapter 2
After a while a respected monk named Subhuti, who was sitting with the other followers, rose from his seat. He bowed and then addressed the Buddha: "Most Honored One, It is wonderful that you given so much knowledge and wisdom to your followers. It is remarkable that you look after our welfare so well." "I have a question to ask you. If sons and daughters of good families want to develop the highest, most fulfilled and awakened mind, if they wish to attain the Highest Perfect Wisdom, what should they do to help quiet their minds and subdue their cravings?" The Buddha replied: "I am mindful of the welfare of my followers. Listen carefully with your full attention, and I will sanswer your question." "If sons and daughters of good families want to develop the highest, most fulfilled and awakened mind, if they wish to attain the Highest Perfect Wisdom and quiet their minds while subduing their cravings, then they should follow what I am about to say to you. They will then be able to subdue their discriminative thoughts and craving desires. It is possible to attain perfect tranquility and clarity of mind by absorbing and dwelling on the teachings I am about to give." Then the Buddha addressed the assembly.
This is more introductory material. Subhuti has asked the Buddha to describe the essence of his teaching. These people have been following the Buddha's example for a while and Subhuti is asking him to explain in a clear way what they should do, how they can quiet their minds and control their desires.