Deuteronomy 16 in one of the chapters in the Torah that contains the mitzvoth to observe the various holidays. It can never be stressed enough that the Torah demands that celebration must entail extending kindnesses to those who are less fortunate.

You shall count off seven weeks; start to count the seven weeks when the sickle is first put to the standing grain. Then you shall observe the Feast of Weeks for the L-RD your God, offering your freewill contribution according as the L-RD your God has blessed you. You shall rejoice before the L-Rd your God with your son and your daughter, your male and female slave, the Levite in your communities, and the stranger, the fatherless, and the widow in your midst, at the place where the L-RD your God will choose to establish His name. Always remember that you were slaves in Egypt, and take care to obey these laws.

After the ingathering from your threshing floor and your vat, you shall hold the Feast of Booths for seven days. You shall rejoice in your festival, with your son and daughter, your male and female slave, the Levite, the stranger, the fatherless, and the widows in your communities. You shall hold festival for the L-RD your God seven days, in the place that the L-Rd will choose; for the L-RD your God will bless all your crops and all your undertakings, and you shall have nothing but joy. (Deuteronomy 16:9-15)

In Mishneh Torah, Hilkhot Yom Tov 6:18, Rambam writes as follows:

And while one eats and drinks himself, it is his duty to feed the stranger, the orphan, the widow, and other poor and unfortunate people, for he who locks the doors to his courtyard and eats and drinks with his wife and family, without giving anything to eat and drink to the poor and bitter in soul - his meal is not a rejoicing in a divine commandment, but a rejoicing in his own stomach. It is of such persons that Scripture says, “Their sacrifices shall be to them as the bread of mourners, all that eat thereof shall be polluted; for their bread is their own appetite” (Hosea 9:4).Rejoicing of this kind is a disgrace to those who indulge in it, as scripture says, “And I will spread dung upon your faces, even the dung of your sacrifices” (Malachi 3:3).

In Hilkhot Hagigah, Chapter Two, Rambam repeats these notions, placing special emphasis on the Levites, who are presumably poor.

(Hilkhot Hagigah 2:14)…When a man sacrifices a festal peace offering or a peace offering of rejoicing he should not eat of it with his children and his wife alone and thing that he thus fulfills his entire duty; but it is incumbent upon him to give joy to the poor and the unfortunate, for it is said, “And the Levite, and the stranger, and the fatherless, and the widow” (Deuteronomy 16:14). In proportion to his riches he should suffer them all to eat and to drink.

And if a man ate his sacrifices and did not suffer these also to rejoice with him, of him it is said: “Their sacrifices shall be to them to be the bread of mourners, all that eat thereof shall become unclean, for their bread shall be for their appetite” (Hosea 9:4).

The duty toward the Levite surpasses all, since he has neither portion nor possession, nor has he any dues from the flesh of the offerings. Therefore a man should invite Levites to his table to give him cause to rejoice. Or he should give them gifts of flesh, together with their tithes, that they may find therein enough for their needs. But he who forsakes the Levite and gives him no cause to rejoice or is dilatory in paying him his tithes at the feast transgresses a negative commandment, for it is said, “Take heed to yourself that you forsake not the Levite”
(Deuteronomy 12:19).

Rambam’s citation of a verse from the beginning of Parashat Re’eh is instructive. Not just the end of the Parashah but the beginning remind us that the objective formal observance of mitzvoth must be accompanied by the subjective feelings of charity towards others and the expression of these feelings by appropriate behaviors.