Reference for Deuteronomy 32:20

וַיֹּ֗אמֶר אַסְתִּ֤ירָה פָנַי֙ מֵהֶ֔ם אֶרְאֶ֖ה מָ֣ה אַחֲרִיתָ֑ם כִּ֣י ד֤וֹר תַּהְפֻּכֹת֙ הֵ֔מָּה בָּנִ֖ים לֹא־אֵמֻ֥ן בָּֽם׃

And He said: ‘I will hide My face from them, I will see what their end shall be; For they are a very froward generation, Children in whom is no faithfulness.