Nadav and Avihu's Sacrilege
suggest reading Beresheet chapter 3
10:1 
ויקחו בני־אהרן נדב ואביהוא אישׁ מחתתו ויתנו בהן אשׁ וישׂימו עליה קטרת ויקריבו לפני יהוה
אשׁ זרה אשׁר לא צוה אתם׃
Vayikkhu venei-Aharon Nadav (נדב) va Avihu (אביהוא) ish makhtato vayitnu vahen esh vayasimu aleiha ketoret vayakrivu lifnei ADONAI esh zarah asher lo tzivah otam:
And Nadav and Avihu, Ben Aharon, each took his fire pan, put fire therein, and put incense thereon, and offered esh zarah (unauthorised fire) before ADONAI (יהוה), which he commanded them not.
10:2 And there went out fire from ADONAI (יהוה), and devoured them, and they died before ADONAI (יהוה).
Then Moshe said to Aharon:
This [is it] that ADONAI (יהוה) spoke, saying:
I will be sanctified in them that come nigh Me, and before all the people I will be glorified.
And Aharon held his peace.
10:4 And Moshe called Misha'el and Eltzafan Benai Uzi'el Dod (uncle) Aharon, and said to them:
Come near, carry your brethren from before the mikdash (sanctuary) out of the camp.
10:5 ויקרבו וישׂאם בכתנתם אל־מחוץ למחנה כאשׁר דבר משׁה׃
Vayikrevu vayisaum bekhutonotam el-mikhutz lamakhaneh kaasher diber Moshe:
So they went near, and carried them in their kuttanot (tunic) out of the camp; as Moshe had said.
10:6 ויאמר משׁה אל־אהרן ולאלעזר ולאיתמר בניו ראשׁיכם אל־תפרעו ובגדיכם לא־תפרמו ולא תמתו ועל כל־העדה יקצף ואחיכם כל־בית ישׂראל יבכו את־השׂרפה אשׁר שׂרף יהוה׃
Vayomer Moshe el-Aharon uleElazar uleItamar banav rasheikhem al-tifrau uvigdeikhem lo-tifromu velo tamutu veal kol-haedah yiktsof vaakheikhem kol-Beit Yisrael yivku et-haserefah asher saraf ADONAI:
Then Moshe said to Aharon, and to Elazar and Itamar his sons:
“Do not uncover your heads or tear your clothes, so you may not die and He will not be angry with the entire congregation. But let your community—the whole house of Yisrael—mourn over the burnt one that ADONAI has burned.
10:7 And you shall not go out from the door of the Ohel Moed (tent of meeting), lest you die: for the anointing oil of ADONAI (יהוה) [is] upon you. And they did according to the word of Moshe.
10:8 And ADONAI spoke to Aharon, saying:
10:9 "Do not drink wine or intoxicating drink, you, nor your banim with you, when you go into the Ohel Moed (tent of meeting), lest you die. It shall be a statute forever throughout your generations,:
10:10 And that you may put difference between kodesh and Chol (unholy) , and between Tamei and Tahor (clean);
10:11 And that you may teach the benai Yisrael all the statutes which ADONAI (יהוה) has spoken to them by the hand of Moshe.
And Moshe spoke to Aharon, and to Ele'azar and to Itamar, his banim that were left, Take the minchah that remains of the offerings of ADONAI (יהוה) made by fire, and eat it without leaven beside the altar: for it [is] most kodesh:
10:13 And you shall eat it in the kodesh place, because it [is] thy due, and thy son' due, of the sacrifices of ADONAI (יהוה) made by fire: for so I am commanded.
10:14 And the wave breast and heave shoulder shall you eat in a Tahor (clean) place; thou, and thy son, and thy daughters with thee: for [they be] thy due, and thy son' due, [which] are given out of the sacrifices of shelamims of the benai Yisrael.
10:15 The heave shoulder and the wave breast shall they bring with the offerings made by fire of the chelev, to wave [it for] a wave offering before ADONAI (יהוה); and it shall be thine, and thy ben' with thee, by a statute for ever; as ADONAI (יהוה) has commanded.
And Moshe diligently sought the goat of the Chatat, and, Hinnei, it was burnt: and he was angry with El'azar and Itamar, the son of Aharon [which were] left [alive], saying,
10:17 Wherefore have you not eaten the Chatat in the kodesh place, seeing it [is] most kodesh, and [Elohim] has given it you to bear the iniquity of the congregation, to make atonement for them before ADONAI (יהוה)?
10:18 Hinnei, the blood of it was not brought in within the kodesh [place]: you should indeed have eaten it in the kodesh [place], as I commanded.
10:19 And Aharon said to Moshe:
Hinnei, this day have they offered their Chatat and their Olah before ADONAI (יהוה); and such things have befallen me: and [if] I had eaten the Chatat to day, should it have been accepted in the sight of ADONAI (יהוה)?
10:20 And when Moshe heard [that], he was content.
fire pans To carry fire to the inside altar (Rashi). Some say that they were like large spoons (Ralbag). According to others, they were pokers for the ashes on the altar (Rashbam; Midrash HaGadol).