Exodus 40:31 Midrash

וְרָחֲצ֣וּ מִמֶּ֔נּוּ מֹשֶׁ֖ה וְאַהֲרֹ֣ן וּבָנָ֑יו אֶת־יְדֵיהֶ֖ם וְאֶת־רַגְלֵיהֶֽם׃

that Moses and Aaron and his sons might wash their hands and their feet thereat;