Deuteronomy 31:9

And Moses wrote down all the words of Yahweh. Then he arose early in the morning and built an altar at the foot of the mountain with twelve pillars for the twelve tribes of Israel.

At that time Yahweh set apart the tribe of Levi to carry the ark of the covenant of Yahweh, to stand before Yahweh to minister for Him and to bless in His name to this day.

that Moses commanded the Levites who carried the ark of the covenant of Yahweh, saying,

“They shall teach Your judgments to Jacob, And Your law to Israel. They shall put incense before You, And whole burnt offerings on Your altar.

and they commanded the people, saying, “When you see the ark of the covenant of Yahweh your God with the Levitical priests carrying it, then you shall set out from your place and go after it.

Then all the elders of Israel came, and the priests carried the ark.

Then Ezra the priest brought the law before the assembly of men, women, and all who could understand when listening, on the first day of the seventh month.