Charles Spurgeon Commentary Numbers 8:9-12

"And thou shalt present the Levites before the tent of meeting: and thou shalt assemble the whole congregation of the children of Israel: and thou shalt present the Levites before Jehovah. And the children of Israel shall lay their hands upon the Levites: and Aaron shall offer the Levites before Jehovah for a wave-offering, on the behalf of the children of Israel, that it may be theirs to do the service of Jehovah. And the Levites shall lay their hands upon the heads of the bullocks: and offer thou the one for a sin-offering, and the other for a burnt-offering, unto Jehovah, to make atonement for the Levites." — Numbers 8:9-12 (ASV)

There is no true way of serving God without the atonement.

Leave that out, and you have left out the vital part of the whole.

What service can we render to the Most High if we begin by disloyalty to him whom God has set forth to be the propitiation for sin, even his dear Son?