Sura al-Ghāfir 40:12

ذَٰلِكُم بِأَنَّهُۥٓ إِذَا دُعِىَ ٱللَّـهُ وَحْدَهُۥ كَفَرْتُمْ وَإِن يُشْرَكْ بِهِۦ تُؤْمِنُوا۟ فَٱلْحُكْمُ لِلَّـهِ ٱلْعَلِىِّ ٱلْكَبِيرِ

dhālikum biannahu idhā duʿiya allāhu waḥdahu kafartum wa-in yushrak bihi tūʾminū fa-l-ḥukmu lillāhi l-ʿaliyyi l-kabīri

(The answer will be:) "This is because, when Allah was invoked as the Only (object of worship), ye did reject Faith, but when partners were joined to Him, ye believed! the Command is with Allah, Most High, Most Great!"