The begging bowl is an important symbol in Buddism.
It is a story told in this religion that says that prior to the period of enlightment of the Buddha was undergoing a process of sacrifice in which he was eating very little food. All of a sudden, he was offered a bowl of rice by a woman by the name of Sujata. He partook from her offering only because he realized that, regardless of his sacrifice, stretching it further would not make him any more austere, in fact, it could hurt him. So he only ate what he needed. After he reached englihtement, he threw away what was left in that bowl and made an oath of poverty.
So, the begging bowl is the only thing the Buddah would carry around. He will only eat whatever the people put in the bowl for him. Only what people will share with him. This is a way to completely renounce all material possessions.
Yet, what this teaches is that Buddhism is not about extremes, but about balance. There is a NEED to find a happy medium between sacrifice and life. There is no need to detach oneself from what's neccesary for the sake of calling it a "good deed". Instead, one must find the perfect middle for it.