A priest must not enter the Temple with his head uncovered

Then Moses said to Aaron and to his sons Eleazar and Ithamar, "Do not uncover your heads nor tear your clothes, so that you will not die and that He will not become wrathful against all the congregation. But your kinsmen, the whole house of Israel, shall bewail the burning which the LORD has brought about.

Hebrew

ו וַיֹּאמֶר מֹשֶׁה אֶל-אַהֲרֹן וּלְאֶלְעָזָר וּלְאִיתָמָר בָּנָיו רָאשֵׁיכֶם אַל-תִּפְרָעוּ וּבִגְדֵיכֶם לֹא-תִפְרֹמוּ, וְלֹא תָמֻתוּ, וְעַל כָּל-הָעֵדָה, יִקְצֹף; וַאֲחֵיכֶם, כָּל-בֵּית יִשְׂרָאֵל--יִבְכּוּ אֶת-הַשְּׂרֵפָה, אֲשֶׁר שָׂרַף יְהוָה.

Greek

6 καὶ εἶπεν Μωυσῆς πρὸς Ααρων καὶ Ελεαζαρ καὶ Ιθαμαρ τοὺς υἱοὺς αὐτοῦ τοὺς καταλελειμμένους Τὴν κεφαλὴν ὑμῶν οὐκ ἀποκιδαρώσετε καὶ τὰ ἱμάτια ὑμῶν οὐ διαρρήξετε, ἵνα μὴ ἀποθάνητε καὶ ἐπὶ πᾶσαν τὴν συναγωγὴν ἔσται θυμός· οἱ ἀδελφοὶ ὑμῶν πᾶς ὁ οἶκος Ισραηλ κλαύσονται τὸν ἐμπυρισμόν, ὃν ἐνεπυρίσθησαν ὑπὸ κυρίου.

• Parashah: Shemini
• Sefer HaChinuch: 149
• Mishneh Torah: Service — Entry into the Temple

• Leviticus 10:6

Enumeration and classification from BibleData. The Greek is the Septuagint reading of the same verse, carried by the source for comparison.