For the development of calm panna is indispensable

The calm of samatha that is temporary freedom from defilements cannot be developed without panna. The panna of samatha must be able to discern the characteristic of calm when it arises, otherwise calm cannot grow. The panna of samatha knows kusala as kusala and akusala as akusala, but it is different from the panna of vipassana since it does not realize kusala and akusala as not self. The concept of self is not eradicated through samatha.

One may think that when one concentrates on one point there are conditions for the arising of calm. However, we should not forget that concentration (samadhi) accompanies each citta. The function of this cetasika is to cause the citta to focus on one object. Thus, there is concentration with akusala citta as well as with kusala citta. If one does not know precisely when the citta is kusala citta and when akusala citta, how can one be sure whether there is right concentration? One may, with attachment, exert a great effort to concentrate, or, if one needs such effort to concentrate, one can easily have aversion. Do we know when there are akusala cittas? If we do not know this, calm cannot be developed. For the development of calm panna is indispensable.