Numbers 8:11-13

ASV_Strongs(i)
  11 H175 and Aaron H5130 shall offer H3881 the Levites H6440 before H3068 Jehovah H8573 for a wave-offering, H1121 on the behalf of the children H3478 of Israel, H5647 that it may be theirs to do H5656 the service H3068 of Jehovah.
  12 H3881 And the Levites H5564 shall lay H3027 their hands H7218 upon the heads H6499 of the bullocks: H6213 and offer H259 thou the one H2403 for a sin-offering, H259 and the other H2403 for a burnt-offering, H3068 unto Jehovah, H3722 to make atonement H3881 for the Levites.
  13 H5975 And thou shalt set H3881 the Levites H6440 before H175 Aaron, H6440 and before H1121 his sons, H5130 and offer H8573 them for a wave-offering H3068 unto Jehovah.