Zaalikum bi annahooo izaa du'iyal laahu wahdahoo kafartum wa iny yushrak bihee tu'minoo; falhukmu lillaahil 'Aliyyil Kabeer
(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!"
Transliteration: Zaalikum bi annahooo izaa du'iyal laahu wahdahoo kafartum wa iny yushrak bihee tu'minoo; falhukmu lillaahil 'Aliyyil Kabeer
Translation (Yusuf Ali): (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!"
This is verse 12 of Surah Ghafar (غَافِر, meaning "The Forgiver"), the 40th surah of the Quran. It is a Meccan surah with 85 total verses.
This verse is referenced in the following Quranic topics: Who goes to Hell.