The letter ‘Inna is to show Magnificence. Whenever Allah U speaks about any affair that indicates His actions, He will say:
﴾إِنّا نَحنُ نَزَّلنَا الذِّكرَ وَإِنّا لَهُ لَحافِظونَ﴿
“Indeed We have sent down the Reminder, and indeed We will preserve it.” [Surah Al-Hijr: 9].
This ‘Inna of Magnificence combines all Attributes that Allah U has made subservient to His Actions by His Power, His Knowledge, His Wisdom and His Greatness:
﴾وَإِنّا عَلىٰ ذَهابٍ بِهِ لَقادِرونَ﴿
“and We are indeed able to take it away.” [Surah Al-Mukminun: 18].