Met Mitzvah

(1) Adonai said to Moses: Speak to the priests, the sons of Aaron, and say to them: None shall defile himself for any [dead] person among his kin, (2) except for the relatives that are closest to him: his mother, his father, his son, his daughter, and his brother; (3) also for a virgin sister, close to him because she has not become someone’s [wife], for her he may defile himself. (4) But he shall not defile himself as a kinsman by marriage.

For his father and his mother he does not become impure, but he does become impure for a met mitzvah. (Bamidbar 6:7) "for his brother:" If he were a high priest or a Nazirite, he may not become tamei, but he does become tamei for a meth-mitzvah. "and for his sister:" What is the intent of this? If one (an ordinary priest) were going to slaughter his Paschal lamb or to circumcise his son, and he hears that one of his kin had died, I might think that he should become impure for them; it is, therefore, written (Ibid.) "he shall not become impure." I might think that he should (also) not become impure for a met mitzvah; it is, therefore, written "and for his sister" — He does not become impure for his sister, but he does become impure for a met mitzvah.

If one must choose between Torah study and tending to a corpse with no one to bury it [met mitzva], the task of burying the met mitzva takes precedence. This is derived from that which is taught in a baraita: One cancels their Torah study to bring out a corpse for burial, and to join a wedding procession and bring in the bride. Similarly, if one must choose between the Temple service and tending to a met mitzva, tending to the met mitzva takes precedence

Our Sages teach: We bring out a corpse before the bride. The explanation is that if a wedding party and a funeral procession meet on the road, the bride goes first...we advance and bring the bride to the huppah and afterward burry the deceased...but after she goes to the huppah, one has to comfort the mourner and rejoice with the groom, one comforts the mourner first, and similarly, feeds the mourner the post-burial meal before the celebratory wedding meal wit the groom...and regarding all of this, it's not the case with a met mitzvah. Since if it's a met mitzvah, they take precedence and postpone Torah study, reading Megillah, a priest or nazir contracting ritual impurity the pascal offering, and circumcision. There is no matter more important than it [met mitzvah] in the entire Torah.

(2) The reward one receives for "accompanying" someone (taharah and burial) is greater than all of the others. This is a statute which Abraham our Patriarch instituted and the path of kindness which he would follow. He would feed wayfarers, provide them with drink, and accompany them. Showing hospitality for guests surpasses receiving the Divine Presence as Genesis 18:3 states: "And he saw and behold there were three people." Accompanying them is greater than showing them hospitality. Our Sages said: "Whoever does not accompany them is considered as if he shed blood."