Having refined or subtle bodies of light, angels move very rapidly and can be found in all realms of existence. They place themselves in our eyelids or in the bodies of other beings to observe the works of God. They also descend into the hearts of Prophets and saintly people to bring them inspiration. Such inspirations are usually from God, but sometimes they come from angels.
Some animals, like honeybees, act according to Divine inspiration. Science asserts that all animals are directed by impulses, but cannot explain what an impulse is and how it occurs. Scientists are trying to discover how migrating birds find their way, how young eels hatched in the waters of Europe find their way to their ancestral waters in the Pacific. Even if we attribute this to information coded in their DNA, this information is assuredly from God, Who knows everything, controls the universe, and assigns angels to direct these creatures' lives. If science says we must not question the existence of such invisible forces as the law of growth in living creatures, it is even more scientific to attribute such forces to angels, God's special servants.
Everything that exists, either as an individual or as a species, has a collective identity and performs a unique, universal function. Each flower displays a superlative design and symmetry and recites, in the tongue of its being, the Names of the Creator manifested on it. The entire Earth performs a universal glorification as though it were a single flower. The vast "ocean" of the heavens praises and glorifies the Majestic Maker of the universe through its suns, moons, and stars. Even inert material bodies, although outwardly inanimate and unconscious, perform a vital function in praising God. Angels represent these immaterial bodies in the world of the inner dimensions of things, and express their praise. In return, these immaterial bodies are the angels' representatives, dwellings, and mosques in this world.
There are various classes of angels. One class is engaged in constant worship; another worships by working. These working angels have functions that resemble human occupations, like shepherds or farmers. In other words, the face of the Earth resembles a general farm, and an appointed angel oversees all of its animal species by the command of the All-Majestic Creator, by His permission and power and strength, and for His sake. Each animal species is overseen by a lesser angel appointed to act as its shepherd.
The face of the Earth is also an arable field in which all plants are sown. Another angel is appointed to oversee all of them in the Name of Almighty God and by His power. Lower ranking angels worship and glorify Almighty God by supervising particular plant species. Archangel Michael, upon him be peace, one of the bearers of God's Throne of Sustenance,  oversees the angels of the highest rank.
Angels who function as shepherds or farmers bear no resemblance to human shepherds or farmers, for their supervision is purely for God's sake, in His Name, and by His power and command. They observe the manifestations of God's Lordship in the species they are assigned to supervise, study the manifestations of Divine Power and Mercy in it, communicate Divine commands to it through inspiration, and arrange its voluntary actions.
Their supervision of plants, in particular, consists of representing in the angelic tongue the plants' glorification in the tongue of their being. In other words, these angels proclaim the praises and exaltations that all plants offer to the Majestic Creator through their lives. These angels also regulate and employ the plants' faculties correctly and direct them toward certain ends. Angels perform such services through their partial willpower and a kind of worship and adoration.  They do not originate or create their acts, for everything bears a stamp particular to the Creator of all things. Only God creates. In short, whatever angels do is worship, and it is therefore not like the ordinary acts of human beings.
Since there is one angel to represent every kind of creature and present its service and worship to the Divine Court, the Prophet's, upon him be peace and blessings, description of angels is entirely reasonable and true. According to him, there are angels with 40,000 heads, each with 40,000 mouths, and 40,000 praises sung by 40,000 tongues in each mouth.
This Prophetic tradition means that angels serve universal purposes, and that some natural creatures worship God with 40,000 heads in 40,000 ways. The firmament, for example, praises the Majestic Creator through its suns and stars; the Earth, although a single body, worships with many thousands of "heads" each with many thousands of "mouths" and each with many thousands of "tongues" Thus this tradition is considered to refer to the angel who represents the Earth in the world of the inner dimensions of things (the world of immaterial bodies).
 Said Nursi says that they have partial will-power, as shown by their response to God's proclaiming to them that He would choose a vicegerent on the Earth. This partial willpower, however, does not cause or enable them to disobey God's orders. As such, their willpower is weaker than our willpower.
The Majestic Maker of this huge palace of creation employs four classes of laborers: angels and other spirit beings; inanimate things and vegetable creations, which are quite important servants working without wages; animals, which serve unconsciously in return for a small wage of food and pleasure; and humanity, which works in awareness of the Majestic Creator's purposes. Men and women learn from everything, and supervise lower-ranking servants in return for wages (reward) here and in the Hereafter.
The first class consists of angels. These beings are never promoted for what they do, for each has a fixed, determined rank and receives a particular pleasure from the work itself as well as a radiance from worship. Their reward is found in their service. Just as we are nourished by and derive pleasure from air and water, light and food, angels are nourished by and receive pleasure from the lights of remembrance and glorification, worship and knowledge, and love of God. Since they are created of light, light sustains them. Even fragrant scents, which are close to light, are enjoyable nourishment for them. Indeed, pure spirits take pleasure in sweet scents.
Angles receive their own reward—elevated bliss—for carrying out the commands of the One Whom they worship, working for His sake, rendering service in His Name, and supervising through His view. They gain honor through their connection with Him, are refreshed by studying His Kingdom's material and immaterial dimensions, and are satisfied by observing His Grace and Majesty's manifestations. The resulting bliss is so elevated bliss that we cannot even begin to comprehend or perceive it.
Angels do not sin or disobey, for they do not have an evil-commanding soul that must be resisted. They have fixed stations, and so are neither promoted nor abased. They have no experience with such negative qualities as envy, rancor, enmity, and all the lusts and animal appetites found in human beings and jinn. They have no gender, do not eat or drink, and do not feel hunger, thirst, or tiredness. Although they receive no wages for their worship, they derive special pleasure from carrying out God's commands, delight in being near to Him, and receive spiritual pleasure from their worship. Praise, worship, recitation of God's Names, and glorification of Him are their nourishment, as are light and sweet fragrances.
On the other hand, we struggle with our evil-commanding soul and Satan. While angels invite us to true guidance, inspire us with belief and good conduct and virtue, and call us to resist the temptations of Satan and our evil-commanding selves, Satan and our evil-commanding selves try to seduce us. A person's life is the history of his or her continuous struggle between angelic inspiration and satanic temptation. This is why we can be elevated to the highest rank or abased to the lowest rank. Also, this is why the elect of humanity, the Prophets and great saints, are higher in rank than the greatest angels, and why ordinary believers are higher than common angels. Also, although angels have more knowledge of God and His Names and Attributes than we do, we are more comprehensive mirrors of God's Names and Attributes due to our developed human senses, our ability to reflect, and our complex nature.
There are different kinds of angels. Besides those deputed to represent and supervise various species and present their worship to God, there are four Archangels and angels who carry God's Throne.  Other other groups of angels are known as Mala'-i A'la (the Highest Council), Nadiyy-i A'la (the Highest Assembly), and Rafiq-i A'la (the Highest Company). Specific angels have been appointed to Paradise and Hell. Angels who record a person's deeds are called Kiramun Katibun (the Noble Recorders), and, as stated in a hadith, 360 of them are responsible for each believer's life. They guard their charges, especially during infancy and old age, pray for them, and ask God to forgive them. Other angels help believers during times of war and attend assemblies that praise and glorify God, as well as study meetings held for God's sake and to benefit people.
Angels, particularly angels of mercy, do not enter houses containing statues or places where dogs are fed, and refrain from close contact with ritually impure people and menstruating women. They also avoid those with bad breath (derived from eating onions or garlic or from smoking), and do not visit those who sever relations with their parents and relatives.
Although God is All-Powerful and can guard everyone by Himself, He may appoint angels to guard His servants. To earn such a guardianship, believers have to do willingly that which is good and establish a close relation with God Almighty. They must have strong belief in God and all other pillars of faith, never abandon regular worship and prayer, lead a disciplined life, and refrain from forbidden things or sinful acts.
Angels helped the believers during the battles of Badr and Uhud, and also during the conquest of Makka. They always help believers who sincerely struggle in the way of God, regardless of time and place.
Belief in angels has many benefits. For example, it provides us some peace and removes our loneliness. The inspiration breathed by angels exhilarates us, enlightens us intellectually, and opens new horizons of knowledge and thought. Awareness of their continuous company also helps us abstain from sin and improper behavior.
We may use some Qur'anic verses, such as the following, to observe angels:
By the loosed ones successively, storming tempestuously; by the scatterers scattering, and the severally severing and those hurling a reminder, excusing or warning. (77:1-6)
By those that pluck out violently; and those that draw out gently; by those that float serenely, and those that outstrip suddenly; by those that direct an affair. (79:1-5)
... in (the Night of Power) the angels and the spirit descend, by the leave of their Lord, upon every command. (97:4)
... a Fire whose fuel is men and stones, and over which are harsh, terrible angels who disobey not God in what He commands them and do what they are commanded. (66:6)
Glory be to Him! Nay, but they are honored servants that outstrip Him not in speech, and perform as He commands. (21:26–27)