The Quran

Preface

وَأَذانٌ مِنَ اللَّهِ وَرَسولِهِ إِلَى النّاسِ يَومَ الحَجِّ الأَكبَرِ أَنَّ اللَّهَ بَريءٌ مِنَ المُشرِكينَ ۙ وَرَسولُهُ ۚ فَإِن تُبتُم فَهُوَ خَيرٌ لَكُم ۖ وَإِن تَوَلَّيتُم فَاعلَموا أَنَّكُم غَيرُ مُعجِزِي اللَّهِ ۗ وَبَشِّرِ الَّذينَ كَفَروا بِعَذابٍ أَليمٍ

Ali Quli Qarai

[This is] an announcement from Allah and His Apostle to all the people on the day of the greater ḥajj:¹ that Allah and His Apostle repudiate the polytheists: If you repent² that is better for you; but if you turn your backs [on Allah], know that you cannot thwart Allah, and inform the faithless of a painful punishment

That is, the tenth of Dhū al-Ḥijjah, the day on which the pilgrims perform some of the major rites of the ḥajj in Minā.
That is, abandon idolatry.