Thank you Sinweiy for Bhikkhu Pesala's message. 
Further explanation of Gong De by 6th Patriarch Hui Neng:
The Sutra of the 6th Patriarch, Hui Neng
One day Prefect Wei entertained the Patriarch and asked him to
preach to a big gathering. At the end of the feast, Prefect Wei
asked him to mount the pulpit (to which the Patriarch consented).
After bowing twice reverently, in company with other officials,
scholars, and commoners, Prefect Wei said, "I have heard what Your
Holiness preached. It is really so deep that it is beyond our mind
and speech, and I have certain doubts which I hope you will clear
up for me." "If you have any doubts," replied the Patriarch,
"please ask, and I will explain." "What you preach are the
fundamental principles taught by Bodhidharma, are they not?" "Yes,"
replied the Patriarch. "I was told," said Prefect Wei, "that at
Bodhidharma's first interview with Emperor Wu of Liang he was asked
what merits the Emperor would get for the work of his life in
building temples, allowing new monks to be ordained (royal consent
was necessary at that time), giving alms and entertaining the
Order; and his reply was that these would bring no meritsar all.
Now, I cannot understand why he gave such an answer. Will you
please explain." "These would bring no merits," replied the
Patriarch. "Don't doubt the words of the Sage. Emperor Wu's
mind was under an erroneous impression, and he did not know the
orthodox teaching. Such deeds as building temples, allowing new
monks to be ordained, giving alms and entertaining the Order will
bring you only felicities, which should not be taken for merits.
Merits are to be found within the Dharmakaya, and they have nothing
to do with practices for attaining felicities." The Patriarch went
on, "Realization of the Essence of Mind is Kung (good deserts), and
equality is Teh (good quality). When our mental activity works
without any impediment, so that we are in a position to know
constantly the true state and the mysterious functioning of our own
mind, we are said to have acquired Kung Teh (merits).
Within, to keep the mind in a humble mood is Kung; and without, to
behave oneself according to propriety is Teh. That all things are
the manifestation of the Essence of Mind is Kung, and that the
quintessence of mind is free from idle thoughts is Teh. Not to go
astray from the Essence of Mind is Kung, and not to pollute the
mind in using it is Teh. If you seek for merits within the
Dharmakaya, and do what I have just said, what you acquire will be
real merits.
He who works for merits does not slight others; and on all
occasions he treats everybody with respect. He who is in the habit
of looking down upon others has not got rid of the erroneous idea
of a self, which indicates his lack of Kung. Because of his egotism
and his habitual contempt for all others, he knows not the real
Essence of Mind; and this shows his lack of Teh. Learned Audience,
when our mental activity works without interruption, then it is
Kung; and when our mind functions in a straightforward manner, then
it is Teh. To train our own mind is Kung, and to train our own body
is Teh.
Learned Audience, merits should be sought within the Essence of
Mind and they cannot be acquired by almsgiving, entertaining the
monks, etc. We should therefore distinguish between felicities and
merits. There is nothing wrong in what our Patriarch said. It is
Emperor Wu himself who did not know the true way."