Who are Angels?

Each of us has two angels who accompany him. These angels take note of

everything we do. They write down our good deeds and our bad deeds. We call

these angels the Writing Angels. There are other angels, too. For example,

Angels in the Quran - Harun Yahya

THE ANGEL POSSESSED OF POWER: JIBRIL (also called Gabriel / Jibreel)

Truly it is the speech of a noble Messenger, (Surat at-Takwir, 19)

He is the Raiser of ranks, the Possessor of the Throne, He sends the Spirit by His command to whichever of His servants He wills so that he may warn mankind about the Day of Meeting: (Surah Ghafir, 15)

Excerpts from 'The Angels' by Sachiko Murata

The Angels

Angels are unseen beings of a luminous and spiritual substance that act as intermediaries between God and the visible world. Belief in their existence enters into the definition of faith itself: "The Messenger believes in what was sent down to him from his Lord, and the believers: Each one believes in God, His angels, His Books, and His Messengers" (Quran II:285; cf. II:177, IV:136).

Noble Angels of Allah

Belief in angels is one of the six pillars of belief or faith without which there is no faith. Whoever does not believe in any of these pillars is not a believer (mu’min). These pillars are belief in: Allaah, His angels, His Books, His Messengers, the Last Day, and that predestination, both good and bad, comes from Allah.

Can Angels Disobey? - The case of Harut and Marut

Concerning Can Angels Disobey? - The case of Harut and Marut contradiction:
Can angels disobey? No angel is arrogant, they all obey Allah [16:49-50], but verse [2:102] relates the story of two angels who sinned.
Verses in question:

What Is Meant by the Holy Spirit in the Qur'an?

QUESTION:
Dear scholars, As-Salamu `alaykum. I was a Christian before, and now I am confused about the definition of the Holy Spirit. What is the Holy Spirit according to Islam? I would like to know the meaning of the Holy Spirit specifically in surat al-Ma'idah (5: 110). Jazakum Allah khayran.