…you shall surely bury him that same day. (Deuteronomy 21:23)
As discussed in the previous mitzvah, an executed idolator was not permitted to remain on the gallows overnight. Rather, he was to be buried on the same day. In fact, it is a positive mitzvah to do so!
We can logically expand the scope of this mitzvah. The Talmud in Sanhedrin (46a) explains that this mitzvah applies to all who were executed by the courts, not just to those few cases that were hanged after execution. If people convicted of the most heinous crimes were entitled to a speedy burial, it goes without saying that normal people, who have not committed such offenses, deserve the same courtesy. Hence, we have the Jewish practice of burying the deceased as quickly as possible.
The word “chesed” refers to acts of kindness. The Talmud in Sotah (14a) tells us that the Torah starts with chesed, when God clothed Adam and Eve, and it ends with chesed, when He buried Moshe. Not only is burying the dead considered a chesed, it is what’s referred to as the “chesed shel emes,” “the true act of kindness.” This is because when a person feeds or clothes or performs any other act of kindness for another person, the possibility exists that the other person might someday repay the favor. When one person buries another, it is a true act of kindness done solely for its own sake without any possibility of reciprocation.
The mitzvah to bury quickly applies in all times and places. It is discussed in the Talmud in tractate Sanhedrin (45b-46b) and is codified in the Shulchan Aruch in Yoreh Deah 357. This mitzvah is #231 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos; it is not listed in the Sefer HaMitzvos HaKatzar of the Chofetz Chaim.