﴿ مَّآ أَصَابَكَ مِنْ حَسَنَةٍۢ فَمِنَ ٱللَّهِ ۖ وَمَآ أَصَابَكَ مِن سَيِّئَةٍۢ فَمِن نَّفْسِكَ ۚ وَأَرْسَلْنَٰكَ لِلنَّاسِ رَسُولًۭا ۚ وَكَفَىٰ بِٱللَّهِ شَهِيدًۭا ﴾

“Whatever good happens to thee is from God; and whatever evil befalls thee is from thyself. AND WE have sent thee [O Muhammad] as an apostle unto all mankind: and none can bear witness [thereto] as God does.”

Whatever good hasana means khayr befalls you O man it is from God it has come to you from His bounty; whatever evil misfortune befalls you is from yourself it has come to you as a necessary consequence of sins you have committed. We have sent you O Muhammad (s) to people as a messenger rasūlan is a circumstantial qualifier for emphasis and God suffices as Witness of your Mission.