Where in Quran can I find where Gabriel revealed to Mohammed?

God is the Greatest, I testify and bear witness that there is no god but God and that Muhammad (peace be upon him) is God's prophet and slave and that the Holy Quran is from God, none is worthy of being worshiped except God, all praise is due to God, God is the King and Protector and Light and Lord and Ruler and Creator of the heavens and the earth and everything in them!
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I recommend the Quran.com app.

(Surah 96: The Clot) : Read: In the Name of your Lord who created. Created man from a clot. Read: And your Lord is the Most Generous. He who taught by the pen. Taught man what he never knew.

Angels are real and exists, it's the Truth. They have wings as described in the Quran. I been lucky and blessed (all thanks is due to God) to have had a Vision of an angel, a quick showing of an angel, she had two white wings, as described again in the Quran.

They are God's worshipping-slaves and do whatever job He Commands them to.

God is Great and Divine and Holy, of course God had to send an angel to Prophet Muhammad (PBUH) in order to convey the message and information (Knowledge) God had to mankind. Never ever could God show Himself in front of Muhammad (pbuh) and be there with him giving him the Quran. Just like God reaveled Himself only in a burning bush to Moses, and we know what happened when Moses asked to see God.

Just seeing an angel in it's pure form itself is almost utterly forbidden.

God had to convey His Message to mankind through elected messengers. Through Scripture, through the pen.

That's the only way.

God is Most Glorified, all praise is due to God, there is no other god besides God nor any worthy of worship except God, and to Him is our Absolutely Certain return.