This reading is from the Torah portion read on Yom Kippur. The complete reading for Yom Kippur is Leviticus 16:1-34 and Numbers 29:7-11.
And this shall be to you a law for all time: In the seventh month, on the tenth day of the month, you shall practice self-denial; and you shall do no manner of work, neither the citizen nor the alien who resides among you. For on this day atonement shall be made for you to cleanse you of all your sins; you shall be clean before the Lord. It shall be a sabbath of complete rest for you, and you shall practice self-denial; it is a law for all time.
The priest who has been anointed and ordained to serve as priest in place of his father shall make expiation. He shall put on the linen vestments, the sacral vestments. He shall purge the innermost Shrine; he shall purge the Tent of Meeting and the altar; and he shall make expiation for the priests and for all the people of the congregation.
This shall be to you a law for all time: to make atonement for the Israelites for all their sins once a year.
And Moses did as the Lord had commanded him.