the basket of consecration

This means the basket contains offerings used while consecrating Aaron and his sons. Alternate translation: "the basket"

as I commanded, saying, 'Aaron and his sons will eat it.'

This has a quotation within a quotation. A direct quotation can be stated as an indirect quotation. Alternate translation: "as I commanded you to do" (See:rc://en/ta/man/translate/figs-quotesinquotes and rc://en/ta/man/translate/figs-quotations)