וְלֹא־יָשִׁ֣יב אֶל־לִבּ֗וֹ וְלֹ֨א דַ֥עַת וְלֹֽא־תְבוּנָה֮ לֵאמֹר֒ חֶצְי֞וֹ שָׂרַ֣פְתִּי בְמוֹ־אֵ֗שׁ וְ֠אַף אָפִ֤יתִי עַל־גֶּחָלָיו֙ לֶ֔חֶם אֶצְלֶ֥ה בָשָׂ֖ר וְאֹכֵ֑ל וְיִתְרוֹ֙ לְתוֹעֵבָ֣ה אֶעֱשֶׂ֔ה לְב֥וּל עֵ֖ץ אֶסְגּֽוֹד׃
And none considereth in his heart, Neither is there knowledge nor understanding to say: ‘I have burned the half of it in the fire; Yea, also I have baked bread upon the coals thereof; I have roasted flesh and eaten it; And shall I make the residue thereof an abomination? Shall I fall down to the stock of a tree?’
Read Kabbalistic (mystical) interpretations of Isaiah 44:19: Zohar and classical Jewish mystical sources, free online.