וַיַּ֥רְא שָׁא֖וּל אֶת־מַחֲנֵ֣ה פְלִשְׁתִּ֑ים וַיִּרָ֕א וַיֶּחֱרַ֥ד לִבּ֖וֹ מְאֹֽד׃
And when Saul saw the host of the Philistines, he was afraid, and his heart trembled greatly.
Read kabbalistic (mystical) interpretation of I Samuel 28:5: and classical mystical sources.