Al-Furqan - 25:60

وَإِذَا قِيلَ لَهُمُ اسْجُدُوا لِلرَّحْمَنِ قَالُوا وَمَا الرَّحْمَنُ أَنَسْجُدُ لِمَا تَأْمُرُنَا وَزَادَهُمْ نُفُورًا
[25:60]
And when it is said to them: Prostrate to the Beneficent Allah, they say: And what is the Allah of beneficence? Shall we prostrate to what you bid us? And it adds to their aversion.
When it is said to them, "Prostrate to (Allah) Most Gracious!", they say, "And what is (Allah) Most Gracious? Shall we prostrate to that which thou commandest us?" And it increases their flight (from the Truth).
And when it is said unto them: Prostrate to the Beneficent! they say: And what is the Beneficent? Are we to prostrate to whatever thou (Muhammad) biddest us? And it increaseth aversion in them.