Too Many Concerns (To Ming Ta-hsiao)
You have too many concerns that preoccupy your mind too urgently.
That’s why you develop all these illnesses.
Just work continuously [on Buddha-remembrance; mindfulness] without any breaks,
without mixing in any other thoughts.
This is the work [for you].
Excessive austerities are not needed.
False thoughts are powerful, but after a long struggle they will submit.
Have no doubts about this.
Do Not Concern Yourself (To Wu Ta-chun)
Do not concern yourself with whether or not you will become enlightened.
Do not concern yourself with existence and non-existence, with inside and outside and in-between.
Do not concern yourself with ‘stopping’ [shammata/samatha] and ‘observing’ [vipashyana/vipasyana].
Do not concern yourself with whether [this method of reciting the buddha-name] is the same or not the same as other Buddhist methods.
If the feeling of doubt does not arise,
do not concern yourself with who it is or who it is not [who is reciting the Buddha-name].
Simply go on reciting the Buddha-name with unified mind and unified intent without a break, pure and unmixed.
Mindfulness of Buddha is the Medicine (To Yu Kuang-hui)
An ancient said:
Mixed mindfulness is the disease.
Mindfulness of Buddha is the medicine.
When Buddha-remembrance is correct, it cures mixed mindfulness.
If you cannot cure it, it is because your mindfulness is not keen.
When miscellaneous thoughts arise,
then use your mind to increase your effort to be mindful of Buddha.
When your spirit is unified and undivided on every syllable [of the Buddha-name],
miscellaneous thoughts will cease by themselves.
Penetrate Through (To Wang Kuang-ti)
Nothing is better than simply reciting the phrase ‘Amitabha Buddha.’
Recite it with your whole mind, with your whole strength, without any other thoughts at all
This is equivalent to the [Zen method of contemplating] the meditation topic ‘No (Wu2)’.
You do not need to keep in mind ‘No’ or any other meditation topic.
If you purify and unify your Buddha-remembrance,
and penetrate through in your recitation of the Buddha-name,
you will penetrate through in all places.
http://www.sinc.sunysb.edu/clubs/buddhism/pureland/chuhung/general.html