Let us now turn our attention to discuss how ‘Kamma’ operates in this world. When we perform a kamma, a portion of it can operate in this life itself. We cannot do this intentionally or at our own bidding. It happens automatically. A second portion of it is reserved to take place during our next life, according to the operation of the laws of kamma or ‘kamma niyama’.

The remainder, if any, can operate during the next life or any subsequent life during our stay in samsara. When we perform wholesome or kusala actions, our thoughts will generate a large quantity of merit or kusal, in the form of somanassa-sahagata Ñāṇa-sampayutta asaṅkhārika or sasaṅkhārika thoughts.

These thoughts operate as groups called ‘citta veethi’ (in Abhidhamma). There are seven thoughts called ‘javana citta’ in a citta veethi. The energy in the first javana citta of a veethi and of the last citta and of the intervening 5 cittas may or may not be the same. But all seven of them are javana citta. The operational energy of the first javana citta in a citta veethi must fruition before the passing of the individual into the next; that is, in the course of this very life or on this side of that particular citta veethi.

This can happen in seven ways. There is this operational energy of that citta veethi while still on this side of that veethi. We tend to believe that the energy generated in a kamma must necessarily occur after the performance of that kamma. But this is not the case. A portion of that kamma can operate while we are still here on this side of that action. It is not necessary for us to await the arising of a new life for this! For instance, when we perform an alms giving we do not have to await a next life for us to reap its benefit.

There are actions which produce their results in this very life. They are called ‘Ditthadhamma Vedaniya Kamma’. After that what comes to effect is the energy of the last javana citta. This operates not in this life but in the immediate life after chuti or exiting from this life. The energy of the other 5 javana cittas operates during any of the lives following the energy of this last javana citta. So in effect, there is the first portion of a kamma that fruitions in this very life. This is ‘Dittha-dhamma-vedanīya-kamma’. Then there is the next portion of it which fruitions in the very next life. This is called ‘Aparāpariya-vedanīya-kamma’.

Finally, there is the last portion of a kamma which can fruition during any of the subsequent lives of the doer of that kamma. This is called ‘Upapajja-vedaniya[1]kamma’. For the noble individual who attains to the highest level of sainthood, namely Arahanta, there could be a large stock of wholesome kamma to his/her credit. They may have given many Sanghika Dana and performed many Sila and Bhāvanā practice sessions. It is said that a single Sanghika Dana can generate an immeasurable quantity of merit (Asankheyya, Appameyya Kusala Kamma).

So what happens to all that virtue when one becomes an Arahant? For an Arahant there is a stock of kamma, good or bad, that can fruition in this very life. (On the negative side, remember the story of Ven Losaka who could not get a square meal even after becoming an Arahant). But the remainder of that stock, whether good or bad, must operate after this life. As an Arahant has no further existence in samsara, or a ‘next life’ so to say, there is no opportunity for this balance of kamma to operate. Therefore it becomes null and void and is called an ‘Ahosi Kamma’.

Ref: The Signs Of Formations By Bhante Jinalankara Thero