וַיֹּ֣אמֶר דָּוִ֗ד אֶל־אֶבְיָתָ֤ר הַכֹּהֵן֙ בֶּן־אֲחִימֶ֔לֶךְ הַגִּֽישָׁה־נָּ֥א לִ֖י הָאֵפֹ֑ד וַיַּגֵּ֧שׁ אֶבְיָתָ֛ר אֶת־הָאֵפֹ֖ד אֶל־דָּוִֽד׃
And David said to Abiathar the priest, the son of Ahimelech: ‘I pray thee, bring me hither the ephod.’ And Abiathar brought thither the ephod to David.
Mishnah Yoma
The high priest performs the service in eight pieces of clothing, and the common priest in four: in tunic, breeches, a headdress, and a sash. The high priest adds the breastpiece, the ephod, the robe and the frontlet. In these were the Urim and Tummim inquired of. But they were not inquired of except by the king, by the head of the court or by one whom the community needs.