וַיֵּ֣דַע דָּוִ֔ד כִּ֣י עָלָ֔יו שָׁא֖וּל מַחֲרִ֣ישׁ הָרָעָ֑ה וַיֹּ֙אמֶר֙ אֶל־אֶבְיָתָ֣ר הַכֹּהֵ֔ן הַגִּ֖ישָׁה הָאֵפֽוֹד׃ (ס)
And David knew that Saul devised mischief against him; and he said to Abiathar the priest: ‘Bring hither the ephod.’
Read kabbalistic (mystical) interpretation of I Samuel 23:9: and classical mystical sources.