Ven Pesala:
The primary goal should be to avoid rebirth in the lower realms.
To be sure of that we should strive to attain at least the first
stage of Stream-winning in this very life. That is not nearly as
difficult at to attain Arahantship and put an end to all
suffering.
I would say that most people have the ability to attain
Stream-winning if they really
work hard for it, but most of us just do not try hard
enough. Very few individuals have killed their own mother or
father, or an Arahant, or caused a schism in the Sangha. No one
alive today could have drawn the blood of a Tathāgata. Only these
five kammas are heavy enough to make the attainment of nibbāna
impossible in this very life.
Then there are those who aspire to attain Omnscient Buddhahood.
The Noblest Aspiration will prevent them from attaining nibbāna
in this very life, even though they have adequate perfections to do
so if they wished to.
Then there are those with mental defects, commonly called mentally
retarded, who lack the wisdom facility. They are also incapable of
meditating effectively as they are incapable of controlling their
minds even to the extent of looking after their own physical
needs.
Then there are those who have obstructive kamma such as insulting a
Noble One. they can also attain nibbāna if they ask for
forgiveness, but not otherwise. That is why there is a tradition of
asking for forgiveness before undertaking a retreat. Those monks
who have committed some offence, but conceal it without confessing
it are in the same position. Lay persons who do not keep the
precepts also have obstructive kamma. Those who disparage
meditation practice, or believe that it is no longer possible to
attain nibbāna in this era, also have obstructive kamma.
Then there are those who hold extreme wrong views such as
annihilationists and eternalists, or those who deny the
Enlightenment of the Buddha or the law of kamma. They can attain
nibbāna if they straighten their wrong views by studying the
Tipitaka and questioning those learned in the Dhamma.
Lastly, there is one other person who is incapable of realising
nibbāna in this very life. Should I tell you who it is? That person
might be embarrassed and stop coming to waste their time posting on
Dhamma Wheel. Nevertheless I should say who it is.
The lazy person is incapable of realising nibbāna.