Gradual instruction/ progressive sermon given by the Buddha when it was necessary to prepare first the listener’s mind before speaking to him on the advanced teaching of the Four Noble Truths. The Blessed One gave gradual instruction in following manner:
* Dana katha – The Blessed One first preach about liberality, wholesome results of liberality, etc.
* Sila katha – The Blessed One then preach about moral conduct and different types of observations ( precepts ) which accomplish moral conduct, wholesome results of moral conduct (Sila), etc.
* Sagga katha – Then, Buddha preach that through the practice of Dana and observation of Sila how one will be born in the Celestial planes (devas and brahmas realms) and heavenly pleasures those celestial beings enjoy in that life. That is sagga katha.
* Kamanam-adinava katha – Then, Blessed One preach these heavenly bliss and heavenly pleasures are not real pleasure. They are fraught with dangers. Then the Buddha explained the dangers, drawbacks, faults, blemishes, vanity and the depravity of sensual pleasures. That is kamanam-adinava katha or adinava katha.
* Okarasankilesa Katha – Then, Buddha explains the thought process taking place when unwholesome Dhammas invade our mind and how it lead to various immoral acts & after effects of such acts, etc.
* Nekkhamma-katha – The remedy for the dangers arise due to sensual pleasures is renunciation. Then Buddha explains the benefits of renunciation, which include attainment of various jhanas through meditation, attainment of various stages of sainthood (Arahant), etc. This is nekkhamma katha.
After these progressive sermons, When the Blessed One perceived that the listener’s mind was prepared, pliant, free from obstacles, elevated and lucid; then Blessed One explains the exalted teaching particular to the Buddhas, that is: Four Noble Truths, Three Characteristics of Existence. At the end of the sermon people attain one out of four stages of Nibbana according to their abilities.
May all beings be well and happy & attain the fruits of Nibbana.