1 Sam 17:55

וְכִרְא֨וֹת שָׁא֜וּל אֶת־דָּוִ֗ד יֹצֵא֙ לִקְרַ֣את הַפְּלִשְׁתִּ֔י אָמַ֗ר אֶל־אַבְנֵר֙ שַׂ֣ר הַצָּבָ֔א בֶּן־מִי־זֶ֥ה הַנַּ֖עַר אַבְנֵ֑ר וַיֹּ֣אמֶר אַבְנֵ֔ר חֵֽי־נַפְשְׁךָ֥ הַמֶּ֖לֶךְ אִם־יָדָֽעְתִּי׃

As Saul had watched David going out to confront the Philistine, he said to Abner the commander of the army, “Abner, whose son is this young man?” “As surely as you live, O king,” Abner replied, “I do not know.”