וַיִּשְׁלַ֗ח אֶֽת־נַעֲרֵי֙ בְּנֵ֣י יִשְׂרָאֵ֔ל וַיַּֽעֲל֖וּ עֹלֹ֑ת וַֽיִּזְבְּח֞וּ זְבָחִ֧ים שְׁלָמִ֛ים לַיהוָ֖ה פָּרִֽים׃
И послал он юношей из сынов Израилевых, которые приносили всесожжения и приносили жертвы мирным волам Господу.
Mishneh Torah, Forbidden Intercourse
Immersion was in the desert before receiving the Torah, as is said, "Sanctify yourselves today and tomorrow; wash your clothes." The offering, as is said, "Send the young ones of Israel to bring elevation offerings" - and everyone in Israel brought them.