וְלֹֽא־דִבֶּ֥ר שָׁא֛וּל מְא֖וּמָה בַּיּ֣וֹם הַה֑וּא כִּ֤י אָמַר֙ מִקְרֶ֣ה ה֔וּא בִּלְתִּ֥י טָה֛וֹר ה֖וּא כִּֽי־לֹ֥א טָהֽוֹר׃ (ס)
Nevertheless Saul spoke not any thing that day; for he thought: ‘Something hath befallen him, he is unclean; surely he is not clean.’
Read kabbalistic (mystical) interpretation of I Samuel 20:26: and classical mystical sources.