Qur'an 16:102

قُلْ نَزَّلَهُۥ رُوحُ ٱلْقُدُسِ مِن رَّبِّكَ بِٱلْحَقِّ لِيُثَبِّتَ ٱلَّذِينَ ءَامَنُوا۟ وَهُدًى وَبُشْرَىٰ لِلْمُسْلِمِينَ

“Say, [O Muḥammad], "The Pure Spirit [i.e., Gabriel] has brought it down from your Lord in truth to make firm those who believe and as guidance and good tidings to the Muslims."”

An-Nahl 16:102 · Saheeh International