Originally, sentient beings
and the quintessence of Buddha were the same in pureness and
brightness. However, when the conditions for the initiation of
ignorance begin to fan like the wind, it eventually produces
ignorance. The ignorance becomes more serious as it gathers
momentum and leads to the transmigration in the Six Realms.
Ignorance, just like the wind, is invisible and one may not be able
to touch them, yet it packs with power so immense that it can
destroy houses and uproot trees.
In the beginning when sentient beings started to transmigrate in
the Six Realms, they were in the realm of Heaven. Then, they
descended to the Human realm. Human beings have seven types of
emotion and six types of lust and because of these they continually
commit negative karma. These led them to descend to the realm of
Asura. Why is the realm of Asura considered to be a good realm? It
is because even heavenly beings can be inflicted by ignorance,
causing them to fight among themselves. The more aggressive
fighters eventually descend to the realm of Asura.
http://www.jenchen.org.sg/vol8no1a.htm
And yes indeed, not everyone can understand the dharma so consider
ourselves lucky that we can. It is the Human Realm that is most
suitable to understand dharma.
From The
Debate of King Milinda
QUOTE
27. Can Everyone Understand the Dhamma?
Do all those who practise correctly attain insight into the Dhamma
or are
there some who do not?
There can be no attaining of insight for those who, though they
practise
correctly, are animals, hungry ghosts, holders of wrong views,
frauds (kuhaka)
matricides, patricides, murderers of Arahants, schismatics,
shedders of the blood
of a Tathāgata, in the robes by theft, gone over to another sect,
violators of
nuns, concealing an offence entailing a meeting of the Order,
sexual deviants
(pandaka) and hermaphrodites (ubhatobyañjaka). Neither is a child
under seven
years of age able to realise the Dhamma.
What is the reason that a child under seven years of age is unable
to attain
insight? For a child is pure in mind and should be ready to realise
the Dhamma.
If a child under seven, O king, could feel desire for things
leading to desire,
hatred for things arousing hatred, could be fooled by misleading
things and could
distinguish between wholesomeness and unwholesomeness then insight
might
be possible for him. However, the mind of a child under seven, O
king, is feeble
and the unconditioned element of nibbāna is weighty and profound.
Therefore,
O king, although he practised correctly, a child of under seven
could not realise
the Dhamma.
Interesting to note that the youngest age to attain awakening is
7 years old, and my friend Vamjok mentions that he remembered 2
instances in the scripture which there were 7 year old novice
attaining Arhantship.