Quran 37:169 from Surah As-Saaffaat on Divine Marvels.
لَكُنَّا عِبَادَ ٱللَّهِ ٱلۡمُخۡلَصِينَ
English translation: Certainly we (would) have been slaves (of) Allah the chosen
Transliteration: lakunna ibada al-lahi al-mukh'lasina