However, whenever Allah U speaks about worship, He will use the singular form as worship is only to Him alone:

﴾إِنَّني﴿“Indeed I” and He says,

﴾إِنَّني أَنَا اللَّهُ لا إِلٰهَ إِلّا أَنا فَاعبُدني وَأَقِمِ الصَّلاةَ لِذِكري﴿

“Indeed I am Allah —there is no god except Me. So, worship Me, and establish the prayer for My remembrance.” [Surah Taha: 14].

Whenever He speaks about His actions, He will use the Inna that consists of every trait and that is the Inna of Majesty and Grandeur.

﴾إِنّا نَحنُ﴿ “Indeed We” [Surah Al-Hijr: 9].

And here, in this verse, He says, ﴾إِنَّا أَرْسَلْنَاكَ﴿“Indeed WE have sent you” Oh Muhammad, so what is your role and concern?