““The contribution of their gifts also belongs to you. I have given all the Israelites’ presentation offerings to you and to your sons and daughters as a permanent statute. Every ceremonially clean person in your house may eat it.
“Tell them further: Once you have presented the best part of the tenth, and it is credited to you Levites as the produce of the threshing floor or the winepress, then you and your household may eat it anywhere. It is your wage in return for your work at the tent of meeting.”
Numbers 18:11, 30-31 HCSB
The Lord is telling the Aaron that the Levite’s will be paid their wages due them for working for Him. The Lord does not treat us as slaves. We are laborers for Him and are due our wages.