thanks for your reply.
but Theravada does not agree with Mahayana view that once a
Buddha or Arhat has attained cessation, there is no way they will
stay or come back to samsara.
According to Milindapanha, it is said that citta (mind) is not
'functioning (appavattam)' in one of the two circumstances: 'when
it has become drowsy and entered bhavanga; and ... when it has
attained cessation' (Miln.300). As this sees citta as not
'functioning' when bhavanga occurs, such a 'non-functioning' citta
could also occur in cessation.
In other words, when we enter into deep dreamless sleep every
night, the mind enters into the state of bhavanga, also known as
the 8th consciousness where there is no content of mind or citta,
in other words the citta lies in a dormant and non functioning
state. Similarly in Nirvana, citta becomes non functioning. However
it does not mean that the functioning of does not have a potential
to arise again as a continuum of wisdom persists. An arhat will not
however be reborn due to the force of karma. If someone liberated
does return it is due to the power of vows and compassion, not
clinging, desire and karma. Theravada texts however generally does
not discuss about this and the main emphasis is on personal
liberation.
For example several passages like M.I.175 and A.IV.454 describe
a monk who 'enters on and abides in the cessation of cognition and
feeling; and having seen by wisdom, his cankers are utterly
destroyed'. This describes the attainment of Arahatship either in
or immediately after the state of cessation. If the former is
meant, then wisdom (panna) can be present in cessation; if this is
so, then so can discernment, for whatever is the object of wisdom
is also known discernment (M.I.292).