וַיִּרָ֥א שָׁא֖וּל מִלִּפְנֵ֣י דָוִ֑ד כִּֽי־הָיָ֤ה יְהוָה֙ עִמּ֔וֹ וּמֵעִ֥ם שָׁא֖וּל סָֽר׃
And Saul was afraid of David, because the LORD was with him, and was departed from Saul.
Read midrashic interpretation of I Samuel 18:12: and classical rabbinic exegesis.