וַיָּבֹ֣א כָל־הָעָ֗ם לְהַבְר֧וֹת אֶת־דָּוִ֛ד לֶ֖חֶם בְּע֣וֹד הַיּ֑וֹם וַיִּשָּׁבַ֨ע דָּוִ֜ד לֵאמֹ֗ר כֹּ֣ה יַעֲשֶׂה־לִּ֤י אֱלֹהִים֙ וְכֹ֣ה יֹסִ֔יף כִּ֣י אִם־לִפְנֵ֧י בֽוֹא־הַשֶּׁ֛מֶשׁ אֶטְעַם־לֶ֖חֶם א֥וֹ כָל־מְאֽוּמָה׃
And all the people came to cause David to eat bread while it was yet day; but David swore, saying: ‘God do so to me, and more also, if I taste bread, or aught else, till the sun be down.’
Read kabbalistic (mystical) interpretation of II Samuel 3:35: and classical mystical sources.