قُلۡ نَزَّلَهُۥ رُوحُ ٱلۡقُدُسِ مِن رَّبِّكَ بِٱلۡحَقِّ لِيُثَبِّتَ ٱلَّذِينَ ءَامَنُواْ وَهُدٗى وَبُشۡرَىٰ لِلۡمُسۡلِمِينَ ١٠٢
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."
Translation: Saheeh International (English)
Each word's meaning and sound
Say to them, O Messenger, This Qur’ān has been brought down by Gabriel (peace be with him) from Allah, may He be glorified, with the truth that contains no error, alteration or distortion, to keep those who have faith in Allah firm on their faith, whether a new part is revealed or a part is abrogated, and to be a guidance for them to the truth and good news for the Muslims about the generous reward that they will obtain.
Al-Mukhtasar in interpreting the Noble Quran