There are pure, holy Spirits, myriads of them, in Heaven enjoying The Presence of The Almighty, glorifying His Holy Name, singing: ‘Holy, Holy, Holy, Lord God of Hosts, Heaven and earth are fully of Thy Glory.’ Thus, they spend their time in giving to Almighty God the external glory, that is due Him from His creatures. They are happy in the fulfillment of these duties and are willing to be so employed for all Eternity.
God has peopled the Heavens with His good Spirits and has surrounded His Throne with them: without any stint, He has called them into existence, till all is filled with them, that God, in His Infinite Wisdom, considered sufficient for His Own Infinite Purpose.
These Angels will be our companions in Heaven for Eternity; to them we can now pray in general. At our request, God, Who has so many Angels, can give us as many as we want for our spiritual service. In fact, God has given each one of us an Angel [Guardian].”
(taken from: Our Favorite Devotions, by Right Rev. Msgr. A.A. Lings, A.D. 1897).
The following prayer/meditation is taken from St. Anselm’s Meditations and Prayers, this is part of his “13th Meditation”
“[61. The nine Choirs of Angels.] Through Thee, for the fulfilling of the behests of The eternal Father, thousands of thousands glide in swift flight twixt heaven and earth, like industrious bees that flit to and fro between their hive and the flowers; a busy throng, innocent and stainless, neither laggard nor disobedient. Through Thee, a hundred times ten thousand stand ministrant in the sanctuary of the temple of highest heaven, staring on The Face of Majesty with a clear unflinching gaze, and sounding forth their harmonious ceaseless hymn to The Glory of The Triune, Undivided Godhead.
Through Thee, the Seraphim burn, the Cherubim shine, the Thrones give judgment.
Thou, O Lord, art a fire that burns and consumes not; and, from their immediate nearness to the fires of Thy Godhead, all the sacred choir of the Seraphim are wrapt in coruscating flame, and pour abroad the overflowing of their blissful ardours on the other armies of Thy battling hosts; and of these we in our turn have tasted of the fulness.
Thou, our God, art very Light; and the hills catch Thy Glory and shed it on Thy people, when Thou dost largely shower forth Thy hidden treasures of wisdom and knowledge on the eyes of the  Cherubim, who fix their nearer gaze on Thee. And from them are lighted in their turn the elect subordinated lamps of Thy marvellous tabernacle, which inextinguishably shine before Thy Face, O Lord.
Thou, King of kings, great awful Judge of judges, dost sit above the lofty Thrones, for they have no higher height than Thine above them, Thrones all life and bliss and uniform profoundest calm; through Thee scanning the ways of Truth, and in Thy Truth giving forth just judgments.
O Lord, our Lord, the holy sublime Dominions worship Thee, expatiating freely in The Mysteries of The Godhead, and, enthroned among the princes of Thy Palace, sustain, with no loftiness of haughty pride, the primacy of an exalted rule.
O Lord, my God, through Thee the stately choir of Principalities reign as mighty noble chiefs over the army of the skies in the princedom of a sweet preëminence, unenvying and unenvied in their excellency, and fulfil The Mysteries of The Divine Will as they read the secret purpose of Thy Heart.
O Lord of the Powers, Thine is their might, as they plunge their flaming brand into the necks of the princes of hell; and fear Thee only, lest these  should be able according to their will to do mischief for our hurt.
Thine, O Virtue of The Father, are all the blessed wonder-working Virtues, whose ministry makes all the whole universe wonder and adore Thee, and, struck dumb awhile at Thy marvellous works, cry out and say, ‘Whatsoever The Lord pleased He hath done, in Heaven, in earth, in the sea, and in all the deeps’ (Ps. cxxxv. 6).
Thine, O Sweet Jesus, are the magnificent Archangels, in whom The Benignity of Thy great Condescension chiefly works; for, glorious satraps of Thy Palace, Thou disdainest not to dispatch them down to this poor world to support and help our lowliness, creatures of clay that we are, and close[ly] allied to dust and ashes. Through them, by Thy Command, the chiefest interests of our salvation are administered, and the profoundest secrets of Thy Supreme Purpose are conveyed to us by them; by them come sicknesses and health to the generations of mankind; by them the kingdoms and the empires of the world subsist. And, chief amongst them do we own Thy Michael, the stalwart standard-bearer and the citizen of Heaven, who stands in advance of the Army of The Living God, and brandishing his champion’s blade thunders  with terrible voice against the marshalled hosts of the enemy. ‘Who is like God?’
And the Blessed Angels, so loveable in their innocence, are they not the choice work of Thy Fingers, O Wisdom of God? For on the day of their creation Thou didst deck them with an incorruptible vestiture for the work of Thy Holy Service. These are the living stars of the higher heaven, the lilies of the inner paradise, the rose-trees planted by the silent-flowing waters of Siloe, with their roots immovably fixed in Thee. O River of peace, O Breath of the garden of delights, O Only Wisdom, ranging round about the circling bourne of Heaven; by Thee they shine, and burn, and glow in perfect wisdom, in virginal chastity, and in the ardours of a deathless love. Blooming in endless youth, they find in our weakness the sphere of their faithful service; for they lead us by the hand like tender guides, and direct our steps as we travel through this darksome world, and ward off the assaults of the enemy, and whisper to us the secrets of Thy Will, and brace up our failing hearts to good, and carry up the incense of our prayers to the Altar of gold, and always supplicate The Face of our Merciful Father for us.”