Breadcrumb: In case you missed it the first time...

Lev. 17 reminds the Israelites that they are absolutely, under no circumstances, allowed to make sacrifices to any other god. If they make an animal sacrifice, they must bring it to the tabernacle door and have it sacrificed upon the altar. (Lev. 17:1-7) I suppose this is just a reminder, in case the Israelites missed the first several dozen times the text commanded them not to sacrifice to other gods.