Ephod is used in this context (and elsewhere, cf. 1 Samuel 23:6) as a shorthand designation for the breastplate of the high priest that contained the Urim and the Thummim. The breastplate was attached to the ephod (garment) of the high priest (Exodus 28:4–14).1 The Urim and Thummim were two stones used to cast lots in order to discern God’s will. Most likely they were of different colouring and they would provide a 'yes' or a 'no' answer to specific questions.2 By these means the LORD provided guidance to the faithful kings under the Old Covenant.
7 Il dit au sacrificateur Abiathar, fils d'Achimélec: Apporte-moi donc l'éphod! Abiathar apporta l'éphod à David.