In Parshat Reeh, chapter 14, sentence 22 the Torah describes that we take a tenth (after terumah and the first tithe ) of our crops and bring them to Jerusalem and eat them there. “you shall eat them before Gd in the place I have chosen.”
A good friend of mine Zachary Prensky (who is currently vacationing in the desert of Morroco) pointed out that usually one brought his tite- produce when he went to Jerusalem for the holidays or “Oleh Regel” going up for the Holiday. There would be lots of people there. Like a big “simchas Torah Kiddush” in modern terms.
Zachary points out that a farmer could have tremendous amount of produce with him and could not possibly consume all this food within the few days he would be in Jerusalem. Zachary explains that all people would come and share their food with others who came. Since you could not eat all the food and it had to be consumed in Jerusalem, it was required that you give it away-share it.
The point of bringing the food was to share your success. To make sure that not only you enjoyed your holiday, but others did as well. Sharing is the true joy of the holiday. Knowing that you are well fed and others are well fed.
Big Shout out to Zach in the desert.