זוהר בראשית — דף רכו ע”ב

Asher is the tribe of oil and joy, whose oil symbolizes the divine anointing oil. One who is anointed with the sacred oil is filled with inner joy. All the oils that came from the portion of Asher were consecrated to holiness. The royal delicacies that Asher provides are the delicacies of the World to Come. Thus Jacob's blessing to Asher evokes the spiritual abundance and joy of its anointing.