Reference for Isaiah 8:20

לְתוֹרָ֖ה וְלִתְעוּדָ֑ה אִם־לֹ֤א יֹֽאמְרוּ֙ כַּדָּבָ֣ר הַזֶּ֔ה אֲשֶׁ֥ר אֵֽין־ל֖וֹ שָֽׁחַר׃

for instruction and for testimony?’—Surely they will speak according to this word, wherein there is no light.—