One of the Buddhist Temples in ancient China was very small, but there were a lot of lay followers coming in to make offerings, to listen to Dharma lectures, and to perform religious rituals.. The Temple needed financial support from the villagers for expansion.
One day, a lay follower brought in a bag of 50 gold coins and gave it to the Buddhist Monk in charge, the Venerable Shing Chu. The Monk took the money and, without saying anything, attended to other matters.
The donor was very unhappy, because in ancient China, 50 gold coins were a lot of money, enough to support an ordinary family for several years - and the Buddhist monk simply took the donation without saying anything, not even a "thank you". So he followed the monk and said, "Your venerable, there are 50 gold coins in the bag which I have just donated to the temple."
"Yes, I know," replied the Monk, "you have just told me earlier."
The lay follower could not stand any longer. "But, I am donating 50 gold coins today, " he raised his voice and said loudly. "It is a large sum of money. How come you don't even acknowledge my donation nor even say, 'thank you'?"
By this time, both of them were walking pass by the Main Buddha Statue in the temple. The Monk replied, "You donate money to the Buddha, why do I have to say "thank you"? You make donations to create good merits for yourself and to make yourself happy. If you consider such donation as a business transaction, then I will give you a 'thank you' note on behave of the Buddha so that you can take it home with you. But from now on, you should consider the Buddha to be your trading partner, not your teacher."
Motto: When you donate, you should not expect anything in return.