Exodus 30:20

בבאם אל אהל מועד WHEN THEY COME INTO THE APPOINTED TENT to burn incense in the morning and at evening, or to sprinkle of the blood of the bullock offered by the anointed High-Priest (Leviticus 4:5, 7) and of the he-goats offered as atonement for the sin of idolatry (all of which services were performed in the interior of the Sanctuary) (Zevachim 19b). ולא ימתו THAT THEY DIE NOT — thus it follows that if they do not wash they will die: You may rightly draw this conclusion for in the Torah laws are sometimes stated only by implication: consequently from what is said here in the negative (that they die not) you may derive the positive (that they will die if they do not observe the law here laid down). אל המזבח [OR WHEN THEY STEP] NEAR THE ALTAR — i. e. the outer altar, in which case there is no entering into the appointed tent but the service is performed in the court.

בְּבֹאָ֞ם אֶל־אֹ֧הֶל מוֹעֵ֛ד יִרְחֲצוּ־מַ֖יִם וְלֹ֣א יָמֻ֑תוּ א֣וֹ בְגִשְׁתָּ֤ם אֶל־הַמִּזְבֵּ֙חַ֙ לְשָׁרֵ֔ת לְהַקְטִ֥יר אִשֶּׁ֖ה לַֽיהֹוָֽה׃

when they go into the Tent of Meeting, they shall wash with water, that they die not; or when they come near to the altar to minister, to burn offering made by fire to the Lord: