The Malbim explains that one of the intentions and benefits of the holidays is to support the kohanim of Hashem and the poor people. These two categories rely on the table of Hashem for sustenance… He says that even after the holiday it is a mitzvah to support the poor with gifts of the harvest. This is of equal value to the offerings to Hashem brought on the holidays which supported the kohanim. These mitzvos are done throughout the year, even after the beis hamikdash was destroyed. Indeed, one who does not give a due share to the poor people, it is as if he withheld his offerings in the beis hamikdash. (Click here fore Hebrew text)
The Rabbeinu Bachye, quoting Rashi, adds one more step to the equation. He quotes the Toras Kohanim almost verbatim, which after asking the question of what this verse is doing at this juncture, the Rabbeinu Bachye, quoting Rashi answers: “From here you learn that whoever gives leket, shichicha and peah to the poor in the proper manner the Torah equates it as if he built the beis hamikdash and brought offerings inside it. I am Hashem your G-D trusted to pay up reward.” (Click here for Hebrew text.)
Leket is 1-2 stalks of produce that falls during harvest; shichicha is bundles forgotten during harvest;peah is produce at the corner of the field. All these should be left for the poor to collect and eat. Maaser ani is a tenth of the produce one must give on the 3rd and 6th year of the shemita cycle. If these mitzvos are fulfilled in exactly the proper manner, it is as if one built the beis hamikdash and brought offerings on the alter, which Hashem concludes in this verse is guaranteed because He is trusted to reward for just deeds.
However if one is to think about it, what is the big deal? One or two stalks fall, a bundle of grain, or the corner of one’s field – they are not so much, especially if many poor people visit the field. Imagine if a person stood outside and gave $1000 to every poor person who came to him; wouldn’t you think that it is a tremendous mitzvah of tzedaka deserving of being equated with bringing an offering in the beis hamikdash? Yet Rashi goes out of his way to emphasize that doing these mitzvos in the proper manner, exactly as Jewish Law prescribes, to its very detail, with all there proper intentions warrants the same reward as building the beis hamikdash and bringing sacrifices on the alter! Anything less or different, even if it looks like a bigger chesed, a better way to benefit the poor, does not have the same rewarding effect. Why?
We are compelled to say that although it might be a tremendous kindness and quite a show of charity to give $1000 to every poor person who passes by, and it is of course deserving of incredible reward, Hashem still runs the world in a systematic way. Therefore, only if that system is running exactly as the Creator created and expects it to run, only then will it function appropriately. Anything different, whether for better or for worse in the eyes of the doer, cannot produce the same results.
Hashem has a plan and gave us insight into the system of how the world runs. It is our job to understand and live by that plan, and not to try to outsmart Hashem and think we can do better, or that we can be good, moral people on our own terms; it won’t produce the desired effects at least in the long run. This doesn’t mean that everything is black or white, all or nothing. There is plenty of gray, and Hashem takes every minute detail into account. But there is a system of how He runs this world, and only living within that system produces perfection.