וַיַּ֣עַשׂ בָּ֗הּ אֶת־אַדְנֵי֙ פֶּ֚תַח אֹ֣הֶל מוֹעֵ֔ד וְאֵת֙ מִזְבַּ֣ח הַנְּחֹ֔שֶׁת וְאֶת־מִכְבַּ֥ר הַנְּחֹ֖שֶׁת אֲשֶׁר־ל֑וֹ וְאֵ֖ת כָּל־כְּלֵ֥י הַמִּזְבֵּֽחַ׃
And therewith he made the sockets to the door of the tent of meeting, and the brazen altar, and the brazen grating for it, and all the vessels of the altar,
Read kabbalistic (mystical) interpretation of Exodus 38:30: and classical mystical sources.