The principles of tea Rikyu (the most revered Japanese master, 16th century) set forth are harmony, respect, purity and tranquility. Harmony is the oneness of host and guest with the flowing rhythms of nature ... Respect is the sincerity of heart that allows one to have an open relationship with the other participants, humbly recognizing their dignity ... Purity is removing the dust of the world from one's heart and mind ... Tranquility comes with the constant practice of harmony, respect, and purity in everyday life. In this state of mind, having found peace and beauty within oneself, a bowl of tea can truly be shared with another.
~ Soshiten Sen