That is because Allah is the Truth, and that what they call upon other than Him is falsehood, and because Allah is the Most High, the Grand.
English Transliteration
Thalika bianna Allaha huwa alhaqqu waanna ma yadAAoona min doonihi albatilu waanna Allaha huwa alAAaliyyu alkabeeru
Tafsir of Verse 30
That is because God -- He is the Truth, and that they call upon apart from Him -- that is the false; and for that God is the All-high, the All-great.
That is because Allah is the (only) Reality, and because whatever else they invoke besides Him is Falsehood; and because Allah,- He is the Most High, Most Great.