The Quran

وَلَئِن سَأَلتَهُم مَن خَلَقَ السَّماواتِ وَالأَرضَ لَيَقولُنَّ اللَّهُ ۚ قُلِ الحَمدُ لِلَّهِ ۚ بَل أَكثَرُهُم لا يَعلَمونَ

Muhammad Asad

AND THUS it is [with most people]: if¹ thou ask them, "Who is it that has created the heavens and the earth?" - they will surely answer, "God." Say: "[Then you ought to know that] all praise is due to God!" - for most of them do not know [what this implies].²

For the above rendering of la'in, see surah 30, note 45.
I.e., they give the above answer unthinkingly, following a vague habit of thought, without realizing that a cognition of God as the Ultimate Cause of all existence logically postulates one's full surrender to Him, and to Him alone.