The words "part" and "allotted portion" mean the same thing and are used for emphasis. Alternate translation: "You may not participate in this work" (See: [[rc://en/ta/man/jit/figs-doublet]])
Here "heart" is a metonym for a person's thoughts or motives. Alternate translation: "you are not right in your heart" or "the motives of your mind are not right" (See: [[rc://en/ta/man/jit/figs-metonymy]])