וַיִּשָּׁ֤בַֽע לָהּ֙ שָׁא֔וּל בַּֽיהוָ֖ה לֵאמֹ֑ר חַי־יְהוָ֕ה אִֽם־יִקְּרֵ֥ךְ עָוֺ֖ן בַּדָּבָ֥ר הַזֶּֽה׃
And Saul swore to her by the LORD, saying: ‘As the LORD liveth, there shall no punishment happen to thee for this thing.’
Read midrashic interpretation of I Samuel 28:10: and classical rabbinic exegesis.