ذٰلِكَ بِأَنَّ اللَّهَ هُوَ الحَقُّ وَأَنَّ ما يَدعونَ مِن دونِهِ الباطِلُ وَأَنَّ اللَّهَ هُوَ العَلِيُّ الكَبيرُ

This is because God is the Absolute Truth, and anything that they invoke beside Him is false. God is the Exalted, the Great.