שִׁבְעַ֣ת יָמִ֗ים יִלְבָּשָׁ֧ם הַכֹּהֵ֛ן תַּחְתָּ֖יו מִבָּנָ֑יו אֲשֶׁ֥ר יָבֹ֛א אֶל־אֹ֥הֶל מוֹעֵ֖ד לְשָׁרֵ֥ת בַּקֹּֽדֶשׁ׃
Seven days shall the son that is priest in his stead put them on, even he who cometh into the tent of meeting to minister in the holy place.
Read kabbalistic (mystical) interpretation of Exodus 29:30: and classical mystical sources.