Islamic Interpretation of Dreams (Ibn-i Sirin):

(Sack) A travelling bag or a sack in a dream represents a coffer, a keeper of one’s secrets, or it could mean a treasure.

Seeing a sack or a bag in a dream also means a trip, or a young son one takes pride to carryover his shoulders.

(Also see Pouch; Sack, Suitcase; Trunk)