וַיְהִי֙ מִֽמָּחֳרָ֔ת וַיֹּ֤אמֶר מֹשֶׁה֙ אֶל־הָעָ֔ם אַתֶּ֥ם חֲטָאתֶ֖ם חֲטָאָ֣ה גְדֹלָ֑ה וְעַתָּה֙ אֶֽעֱלֶ֣ה אֶל־יְהוָ֔ה אוּלַ֥י אֲכַפְּרָ֖ה בְּעַ֥ד חַטַּאתְכֶֽם׃
And it came to pass on the morrow, that Moses said unto the people: ‘Ye have sinned a great sin; and now I will go up unto the LORD, peradventure I shall make atonement for your sin.’
Read kabbalistic (mystical) interpretation of Exodus 32:30: and classical mystical sources.