Believing in the unseen world of angels is an important part of Islam it is the second pillar of belief, after believing in Allah (God).

The angels are being that we cannot see but we know them as much as Allah told us in His book (the Qur'an), or His Messenger Muhammad (peace be upon him) informed us.

 Allah created the angels from light as stated by Prophet Muhammad (peace be upon him): “The angels were created from light, the Jinn (demons) were created from dark flames of fire…”

 Angels are completely obedient to Allah and worship Him alone and Muslims do not worship angels since they among Allah's creatures and also have no power to do either good or harm, except by the Will of Allah.

Even though angels were created before humans they had been ordered to prostrate to Adam. Allah says:

 "And when we said to the angels prostrate to Adam and they did…" (Qur'an 18:50)

The Names of Angels

Muslims believe in specific angels mentioned in the Islamic sources like Jibreel (Gabriel), Mika'eel (Michael), Israfeel, Malik - the guard over Hell, and others. Of these, only Gabriel and Michael are mentioned in the Bible.

The Number of Angels

No one knows the number of angels. Allah says:

"No one knows the number of your Lord's soldiers except Him" (Qur'an 74:31)

The tasks of Angels

Some angels are put in charge of executing God’s laws in the physical world.  Michael is responsible for rain and directing it wherever Allah (God) wishes.  He has helpers who assist him by the command of his Lord (Allah); they direct the winds and clouds as God wills.  Another angel is Israfeel who is responsible for blowing the Horn at the onset of the Day of Judgment. The Angel of Death and his assistants are responsible for taking souls out of the bodies at the time of death God says in the Qur'an (32:11)

“Say: the Angel of Death, put in charge of you, will (duly) take your souls, then shall you be brought back to your Lord.”

By Fatma Dawod

References:

 http://studentorgs.utexas.edu/islam/resources/beliefs/angels2.html

http://www.islamreligion.com/articles/41/

http://www.islamawareness.net/Jinn/angels.html