4:166
لَّـٰكِنِ ٱللَّهُ يَشْهَدُ بِمَآ أَنزَلَ إِلَيْكَ ۖ أَنزَلَهُۥ بِعِلْمِهِۦ ۖ وَٱلْمَلَـٰٓئِكَةُ يَشْهَدُونَ ۚ وَكَفَىٰ بِٱللَّهِ شَهِيدًا
lākini l-lahu yashhadu bimā anzala ilayka anzalahu biʿil'mihi wal-malāikatu yashhadūna wakafā bil-lahi shahīdan
But God Himself bears witness to what He has sent down to you––He sent it down with His full knowledge- the angels too bear witness, though God is sufficient witness.
But Allâh bears witness to that which He has sent down (the Qur’ân) unto you (O Muhammad صلى الله عليه وسلم); He has sent it down with His Knowledge, and the angels bear witness. And Allâh is All-Sufficient as a Witness.